Which processor would u pick if u were building a rig right now? I will be watercooling and im hoping for a 4.0 ghz overclock. I will be using a DFI X48 T2R, so i should be able to manage a high fsb.

 
Q9450.  

just wondering have u seen any reports of a someone achieving 4.0ghz on a Q9450 with water cooling? NVM ive found some.

Since I'm poor, I'd go for the Q6600. Less performance for much less money.

I would consider the Q6700 its cheap now and has 10x multiplier.

My Q9450 will not post Windowz past 3.4, I can post at 3.5, but windowz locks up. My 680i board is stuck at the 428-435 FSB, and is done.
 
The 790i does much better, and one site had the x38 board at 3.7 with it.
 
Temps are the same from 2.66 to 3.4.
 
Q6700 is ok price wise, and multi wise, but most stall out at 3.6 or less, and it needs to hit ~3.8 to equal the 9450 at 3.4.

Doubt you will hit 4ghz with any of them. I would bet you'll come closest with the Q9450. If nothing else it has more cache. Multiplier is better on the Q6700 at 10x.

What makes you say that? The Q9450 can potentially hit 4.5GHz, given that the motherboard can. Also, in Anandtech, they hit 4.0GHz using water cooling with a Q6600.

 
Problem is the motherboards. Many start to get unstable at the FSBs that a Q9450 would need to go that high. Then there's the heat problem. I'm not saying its impossible, but it gets more difficult and surely can't be depended upon.
 
@OP-Between the Q6600 and the Q9450, I'd choose the Q9450. That said, if you can afford a Q9550, you would have an easier time getting high clock with the slightly higher multiplier.

Well, that's why I said "given that the motherboard can", which probably can't.    
 
An X48, which most likely can do 500MHz+ FSB speeds, should be able to get the Q9450 up to 4GHz. Heat would be another issue.
 
Until the Q9450 drops below $320, the Q6600 still remains my top choice for Quadcore.

i have had mine up to 3.6 on a watercooled setup on a rampage formula without screwing with the voltages.

I would get the newer Q9450 because it has more cache. (12mb vs 8mb)
Can't remember where, maybe you can google it, but I read a very intresting review where they use dual cores to test the influence of cache.
Different models with different cache were under and overclocked to get the same Ghz and then to took fps benchmarks. More cache was clearly a big advantage.  
Look at some clock to clock Q6600 vs Q9450 (both at same Mhz) and the Q9450 will win. It also hase some extra features like newer SSE.
The Q9450 might overclock a bit less due to the lower multiplier but I think it will still be faster.
The Q6600 is cheap now but that a very different discussion.
These are my humble thoughts, good luck!

has anyone found any reviews comparing just quad cores, ive been looking at a Q6700, liked the 10x mult... but not sure if going with one w/ 1333 fsb or more cache is worth it, kinda waiting on toms or a site to do a quad core shoot out. I remember when the prescotts had more cache and more heat but neglidgable speed, dont want to end up making a mistake...

I'm doing a lot of video editing and the Q9450 has a new instruction set that can speed things up by 30% to 40% (estimates I hear).  So I went with it.
 
For anything other then video editing I would have stayed with the Q6600.  It's a great chip that's been around for a long time.

I've got a q9450.  I highly recomend either putting some really good cooling on your northbridge, or looking for a proc with a higher multiplier.  I can run 3.6Ghz on air, but I'd be scared of the temps at 500Mhz FSB.
 
Good luck.