Hi Everyone,
 
I picked up a Q9450 for $280 at Microcenter. Now I need to get the rest of the system. I already have a case, 550W psu, HD 4850, and the drives. I have about $300 left for the motherboard, ram, and a hsf for cpu. I'm looking to get 3.2 - 3.6 ghz out of the cpu. Anyone know of a good combination to help me get there? Here's what I'm looking at so far:
 
Motherboard: P45 chipset (Asus, Gigabyte, Biostar)  
 
RAM: 2x2GB kit
 
HSF: no idea (been out of the loop for a while)
 
I'll be gaming and running adobe apps on this machine. Tips and advice appreciated.

about ~$285 (plus $35 in rebates)
What other hardware you planning to use.  It's also good idea to mention the case you have and check to be sure that big HSF fits.

Thanks! Looks good. Here are my full specs:
 
Q9450 | p180b case | Antec 550W | HD 4850 | Seagate 250 GB + WD 640 GB | MB? | RAM?  
 
Is there a recommended thermal compound for that hsf?

That HSF comes with it's own "high performance" thermal grease.
My current favorite is Arctic Cooling MX-2
 
Shouldnt be any problem with the other hardware you'll be using.  

I would suggest an ASUS P5Q Pro ($149 Newegg)

Out of your price range, and cannot crossfire, but the 790i boards hit 3.4 with the Q9450 on auto, just by unlinking the fsb and memory.
 
3.6 was easy with a bump in voltage to the cpu and NB, didn't attempt any higher.
 
Get a good cooler, though, as the quads run 15c hotter on idle than the C2D's do, and hit the roof on load.
 
Love the p180 case, too. Cool and quiet.

Thanks for the replies. Here's what I'm looking at now:
 
RAM: 2x2GB Mushkin DDR2-800 4-4-4-12 (Is it worth the +$20 for cas 4?)
http://www.newegg.com/Product/Prod [...] 6820146726
 
HSF: Xigmatek S1283 + Retention Bracket
http://www.newegg.com/Product/Prod [...] 6835233003
http://www.newegg.com/Product/Prod [...] 6835233019
 
MB: Asus P5Q-E or Biostar TPower i45?
http://www.newegg.com/Product/Prod [...] &Tpk=p5q-e
http://www.newegg.com/Product/Prod [...] star%2bi45
 
That puts me a little over budget, but acceptable. One thing I should mention is I will be using my existing copy of XP x64. I checked the manufacture's websites and didn't see any compatibility issues, but if you've heard of any please let me know
 
I'm leaning towards the biostar motherboard. What do you guys think?

Either motherboard would be an excellent choice.
Compare them side by side for a feature check.  Read the customer reviews on NewEgg.  Read a couple reviews of the motherboards if you can.  Check the MBs websites and look over the features and manual (look under the Manufacturer Info tab).  
 
CL4 vs CL5 on RAM worth $20?  It does offer better performance but the increase is very slight, slight enough to probably not be noticed. Usually RAM is not something you have to spend extra on if you have a tight budget.

Check the whole review to get a better idea.  Choosing the Right Memory for Core 2 Duo Platform
 
There is always some differences between the specs, the SPDs and best capability that the RAM can provice with tweaking (used as an example - not the same model you listed).

 

Great Article. Thanks.  I think I've settled on the P5Q for $130.

http://www.newegg.com/Product/Prod [...] 6813131295

I don't need crossfire and this board looks like one of the best for the price. I will probably go for a 3.2 ghz overclock. (400x8). I'm more interested in longterm stability and reliability than maxing out the cpu.

Edit: Nevermind. The 24 pin placement on that board is horrible. Will keep looking...

Okay, after alot of research I went with the following:
 
Q9450 | p180b case | Antec 550W | HD 4850 | Seagate 250 GB + WD 640 GB
 
MB: Asus P5Q-E
http://www.newegg.com/Product/Prod [...] &Tpk=p5q-e
 
RAM: Corsair XMS2 2x2GB
http://www.newegg.com/Product/Prod [...] 6820145184
 
HSF: Zerotherm Zen
http://www.newegg.com/Product/Prod [...] herm%2bzen
 
Will post a followup once I finish the build

Got the system up and running last night! Everything fit and booted on the first try. I enabled AHCI and installed XP x64 using slipstreamed drivers without a hitch. Currently undergoing stress testing at stock settings. Looks solid. Will update later with some overclocking results and pics. The VID on my chip is 1.25, but I can work with it.

Here's the final component list:

Case:  Antec P180B
PS:     Antec Neo HE 550W
MB:    Asus P5Q-E
CPU:   Intel Q9450
RAM:  2x2GB Corsair XMS2 DHX PC6400 CL4
GPU:   Asus HD 4850
HD1:   Seagate 250GB (System)
HD2:   WD 640 GB (Data)
ODD:  Pioneer DVD-RW
HSF:   Zerotherm Zen

Quick update. Got the cpu up to 8*400=3.2GHz on stock voltage (1.25v). No problems whatsoever. The memory is running at 800Mhz 4-4-4-12 @ 2.0v, which is .1v under spec. I ran a stress test last night and this build is incredibly stable. I maxed out all of the cores using prime95 and looped the 3dmark06 SM3 tests on top of it.  
 
8 hours and 47 minutes later: 0 warnings 0 errors
 
Max temps:
CPU cores: 61C 60C 58C 58C
MB: 48C  
Case: 35C
GPU: 79C
 
I could push it harder, but I'm very happy with the stability and performance I'm getting now. Although I'm sure one day I will max it out just for fun
 
Just a side note. I had an issue with a short on the initial build. After reseating the everything it went away and I haven't seen it since. I have a feeling it was my fault. Forgot to remove an old MB standoff and it made contact with some traces... dumb mistake, but I hope it helps someone else.