Its been several years since I have built a gaming system (2 kids and wife have taken the spare money) but my old P4 systems is starting to get a bit slow.
 
I am looking to get a very solid overclockable gaming system but don't need the bleeding edge technology.  Would like to end up with a system that will last me another 3-4 years. (I mainly play MMORPG)  
 
I would like to get opinions on couple matters
1) I currently have a Soundblaster X-Fi sound card that I can reuse (is this still decent card?)
2) I have an extra refurbished PNY 8600 GTS that I was going to use in the system.
 Would it be better to do SLI with card I have (save money) or just upgrade to a very good single video card.  Either way I plan to get a SLI motherboard so I can upgrade the video cards in the future.
3) Would you recommend an SSD drive or would a raptor 10k drive be just as good for my money
4) I would like to over clock and wondering if a watercooling system would be worth it
 
 
CPU                  Intel BX80562Q6600                                        $221.94
CPU Cooler       Thermalright IFX-14 Heatsink                           $70.00
Motherboard    Asus P5N-T Deluxe                                            $258.50
RAM               Crucial Ballistix DDR2 800 PC2-6400 - 4 GB      $115.98
Case               Antec Nine Hundred                                         $115.99
Power               PC Power & Cooling Silencer S75Q 750W        $159.99
Hard Drive        Western Digital WD360ADFD                            $114.00
DVD-RW            2x Sony Optiarc DVD-RW                                  $65.00
 
                                                                         Base System    $1127.00
 
Video Card        
Option 1Graphics             EVGA GeForce 8800GTX, 768 MB                        $404.59
Option 2 Graphics             GeForce 8600GTS VCG86GTSXPB                       $126.99
                                                (in SLI mode with 1 I have)

How big is the monitor u will be using?  SLI is a waste of money unless its like 24"+.  In other words i dont promote it.  If you want the best frames, get an 8800 GTS and be happy unless the 8600 GTS u have is enough.  If so wait for the RV770s and 10 series (rumors) in summer.  For "future" SLI, is sort of stupid because by the time u want to get a second card the one u want will be hard to find and one of the new generation cards will beat the crap out of the 2 cards.
 
For overclocking and pushing things to the limit, Nvidia chipsets are no good.  If you can drop the SLI and get a P35 motherboard like the Asus P5K-E (good quad overclocker).
Watercooling is not necessary unless u want extreme overclocks.  Its also not very cost effective like air cooling.  It would cost $300+ for a good watercooling system.
That IFX is a great cooler but its big and expensive.  Get its little brother the Thermalright Ultra 120 Extreme.  Its size is a little more bearable and depending on what fans u use (u need to get one for these), the 120 can perform just as well or slightly better than the IFX.
 
Never in my life (now) would I recommend SSD or a raptor.  Raptors are outdated.  Newer large drives cost the same, store more, and perform just as fast (unless .4 seconds matters to u).  SSD atm are crazy expensive and just a waste of money.  In the future when they fully replace HDDs will they be effective for their cost.
 
That soundblaster is a fine card and will be better than onboard.  I generally dont tell ppl to get soundcards cause u rarely hear a difference but since u got it, use it.  Be wary of bad drivers with Vista!!!!
 
Do u need 2 drives, or do u do a lot of burning?

1) What resoultion do you play the game at? ... if its not more than 1650* you don't need SLI ... SLI is not quite worth the money as of now.... and there are many horror stories regarding nvidia mobos/drivers ... it would be advisable to stick to an excellent Non SLI mobo ... Gigabyte GA-P35-DS3L is  the very best out there

2) I strongly suggest you stick with your 8600 for the time being... the spanking new ATI RV770 cards would be out by June.

3) The 500GB 7200 rpm Seagate HD is a much better buy than any 10k rpm HD... Seagate ST3500320AS 7200.11 costs $110. ($90 on ZZF)

4) Do you use Vista or XP ... if you use Vista then get 4GB of RAM,... XP doesn't recognize 4GB.

5) Watercooling is VERY expensive right now...you're better off with Air cooling .. the Xigmatex HDT S1283 is the cooler boss out there right now.

6) The 750W PSU is overkill...get the Corsair 550VX or 620HX.

^^ Silver posted more or less the same before me

I am currently using an Acer 22" widescreen monitor 1680x1050 (and I would really like to use Dual monitors) as I sometimes run 2 eq2 sessions in windowed mode and its REALLY nice to have 2 monitors)  (this is one reason I am upgrading actually... when I try to run 2 monitors at 1680x1050 my graphics card is overheating_
 
I am not sold on SLI, was just thinking of it as an option since I basically got a free 8600GTS as a replacement.  I am more than comfortable using one i have until the new cards come out
 
Ideally I would be running Vista64 (but I happen to have several XP Pro licenses that I am not using, I run my own networking business) so I could go either way
 
I would use 2 DVD drives quite a bit since I often have to copy driver CD's for my clients.
 
Power Supply: Good to know that its overkill.. I am from old school where could not have too much power given the graphics cards at the time
 
Hard Drives:  One thing I forgot to put in... I would really like to run 2 drives in a Raid1 Mode.  Unless there is a motherboard out there that supports Raid5 then I would just get 3 drives and do striped set with parity

I was reading up on your post and thought I should mention.
Running dual monitors with SLI is a HUGE pain.  Drivers do not currently exist to do it.  Therefore, I would really stick to a solid single card solution.  A single 8800 GT can be had for less than 180$ and should provide you with ample power for dual 1680 X 1050.  If not the 8800 GTS might be a better option, but is likely to cost around 200$.  Just thought I'd put in my two cents.

I suggest you go for something like this
 
Q6600
TRUE + good fan (e.g SFF21F)/Xiggy S1283
GA-P35-DS3L/Abit Ip35-E/Asus P5k-E (GA-P35-DS3R OR Abit Ip35/Ip35 Pro OR Asus P5k Deluxe/Premium for Raid)
G.Skill Pc2-6400 4Gb (this one http://www.newegg.com/Product/Prod [...] L5D-4GBPQ)
Case of your choice
Corsair Hx620/Hx520 for psu (you really could run that on a 400w quality psu)
Seagate 7200.11 500Gb OR Wd6400aaks (320gb per platter) OR one of the Samsung F1s (f1>6400aaks>7200.11 500gb) (if you really want RAID you could also take a look at the seagate 7200.11 single platter 320gb drive)
88800GTS G92 512mb
Case of your choice (ones i like are antec 900/cm690 or tt armor/cm stacker for more room)
Vista 64-bit
 
I'm not sure if the ICH9R can support RAID 5, that's something you'll have to find out, if it doesn't i'm sure you can find a raid controller somewhere

1. the 8600gts is not a good card for gaming.  
2. if you want to go multi-card multi-monitor, then ATi is the company to gun for.

CPU                    Intel BX80562Q6600                                    $221.94
CPU Cooler         XIGMATEK HDT-S1283                                  $39.99
Motherboard      Gigabyte GA-EP35-DS3R                               $137.91  
RAM                 Crucial Ballistix DDR2 800 PC2-6400 - 4 GB  $115.98
Case                Antec Nine Hundred                                      $115.995
Power                Corsair Power Supply CMPSU-620HX            $140.00
Hard Drive2        Seagate ST3500320AS 7200.11                   $112.46
DVD-RW             2x Sony Optiarc DVD-RW                               $65.00
 
                Total Price               $949.23
 
Well taking into consideration the feedback everyone (and thank you all for the info and idea's) this is the system I came up with... Should give me a good processer/motherboard and memory for overclocking and enough of a power supply for any peripherals/upgrades later.  and the ability to do my Raid array.  Will have to think about the hard drive config... thinking a smaller fast drive for the OS installation and 2 larger drives in the raid array for storage.   Am going to sleep on this then look at it again in the morning and see if there is anything I am forgetting here (and amd_fanboi I agree that the 8600gts is not optimal card for gaming, but it was free and will tide me over until I can afford a higher end video card)

You're good to go. Though you might find a cheaper case.

You can save a bit by going for the g.skill instead of ballistix

CPU   Intel       BX80562Q6600      $221.94
CPU Cooler     XIGMATEK    HDT-S1283        $39.99
Motherboard    ASUS      P5K-E/WIFI-AP LGA 775 Intel P35  $149.99
RAM   G.SKILL   4GB (2 x 2GB) DDR2 SDRAM DDR2 800 $74.99
Case   COOLER MASTER  Centurion 5 CAC-T05-UW    $53.95
Power Supply   Corsair      CMPSU-620HX       $140.00
Hard Drive      Seagate       2x ST3250410AS 250GB 7200 RPM 16MB $130.00
DVD-RW              Sony        2x  Optiarc DVD-RW       $65.00
          Total Price        $875.86
 
OK,  Take #3....  
Solid processor that I can overclock,  
good cooling fan,  
Motherboard has Raid controller and a couple other nice extras,  
went a bit cheap on the memory but ya cant beat the price.
Coolermaster case just plan nice and priced right
the 2 Hard drives are solid drives and will be perfect for raid1
 
I think this is a pretty sweet setup for price/performance now.  Thanks again for everyones input

Looks solid to me. Go for it!