I have been able to get my hands on a OEM Q9300 M1 stepping.  I have been planning to replace my current system (Athlon 64 x2 4400+, 4 GB RAM, 6600 GS) since my son needs a PC - give him my existing one and build another for myself that can meet my needs for the next 4-5 years.
 
I am not operating under a strict budget but am trying to get the most value for my money.  I considered the E8400, the Q6600 but was able to get a Q9300 for <$300 which is ~$40 more than the others - worth it, I think, since I get both the quad core and the 45 nm technology.
 
I am not a heavy gamer but will be using the system occassionally to play some games, Flight Sim, Ghost Recon, etc. as and when time permits.  I plan to move from XP to Ubuntu but will be using XP under VMware since there are still many win-apps that I cannot find satisfactory Linux alternatives for (Quicken, Photoshop, Premiere, etc.).  I am hoping that the quad core will allow me to get reasonable performance for XP/VMware when doing video editing in Premiere.  If not, then dual boot as and when needed.  I also do a significant amount of ripping and video encoding which again the quad cores are shown to be good at.
 
This is what I am plannning:
Intel Quad Core Q9300 - $300
GIGABYTE GA-EP35-DS3P LGA 775 Intel P35 - $150
EVGA 512-P3-N801-AR GeForce 8800GT 512MB - $200 (after MIR)
G.SKILL 4GB(2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) - $145
ZALMAN CNPS9700 LED 110mm 2 Ball CPU Cooler - $55
Antec P182 Gun Metal Black - $140
Thermaltake ATX 12V 2.2 & EPS 12V version 700W Power Supply - $140 (after MIR)
ASUS Black SATA DVD-ROM Drive Model DVD-E616A3T OEM - $19
Rosewill RCR-102 52-in-1 USB 2.0 Card Reader - $15
Pioneer 20X DVD±R DVD Burner Black - $30
SCEPTRE X24WG-1080P Black 24" 2ms Widescreen LCD Monitor - $330 (after MIR)
 
About $1550 all in.
 
Some questions I hope to have your inputs on (this is my first full build though I have replaced components and tweaked stuff before):
 
- Not into extreme overclocking but would like to OC a bit to get a little more speed out of the system without having to make drastic mods or water cooling. Can I do this with this set up?
 
- The Q9300 is with the M1 stepping - is this a good thing or something to avoid?
 
- Will all this fit comfortably in the case I have selected?
 
- Any options to reduce costs with no or marginal hits to performance?  For example, there are cheaper PSUs available but this one is modular and I think that offers significant benefits in building/cooling the case?  Do I need a 8800 GT or would a cheaper 8800GS or 8600GT be sufficient?
 
- am I missing anything?
 
Thanks

I forgot to add - I will be re-using two of my SATA hard drives from my current PC (200 GB and 120 GB), so have not included hard drives in my config above.

You can get the Q6600 much cheaper, around $240 now, you surely also do not need a 700watt power supply for a 8800GT, thats also a pretty poor card as far as cooling goes, it works great but doesn't cool very well and most are being RMA'd constantly for artifact issues due to the memory overheating. I'm using a Thermaltake Soprano with 3-120mm fans and a dual slot Akimbo cooler on the 8800GT and it still runs hot as hell, only way to solve it is Rivatuner or Ntune. The new cooler basically does nothing better than stock one other than exhaust the hot air out the case a bit better. To be honest with you I had better peformance in Flight Sim with my 8800GTS than with my 8800GT.

I can't comment about the 8800GT as I am still running a 8800GTS 640.  The Q9300 vs the Q6600 seems to be pretty much a toss up in performance but the 45mm chips are more efficient and run cooler.   So if you already have the Q9300, be happy, work it up and let us know what can be done with it.  Also you may not need the 700w psu at present but I wouldn't go much below a quality 600w for overclocking a quad.  I have the PCP&P Silencer 610w for my Q6600.

Thanks, I looked at the 8800GTS and yes, it will be more than adequate for my needs.  It is available for $160 EVGA.  Will switch to this.
 
Does the PCI-E v2 make a difference?  Are there any issues using PCI-E v2 vs. PCI-E cards in the mobo above?
 
I would not mind springing the extra $50 for the Q9300 if it has a few benefits e.g. cooler and more efficient, but also it supports 1333 Mhz bus vs. the 1066 on the Q6600. It also has SSE4, which is a little future proofing for apps that will start to incorporate this.  And without any OCing, the Q9300 offers about 7% better performance over the Q6600 though it has a smaller cache (per xbitlabs).  However, the downside is that it is currently considered to less OC-able than the Q6600, topping out at ~3.3 Ghz - but I am not into extreme OC-ing, if I can push it to 2.8-3.0 Ghz, I will be ecstatic, stock clock will be fine too.