Need help with building new PC

Okay.. so am going to uni on september.. and am going to (have to anyways) purchase a new pc. Now, am thinking if its worth getting a beat PC, alongside a laptop to carry with me in uni (studying computer science so ill prolly need a powerful enuf pc for it + a good gaming rig), or get a beast laptop and use that everywhere.

Thats irrelevant tho to my next question. I currency got an AMD 64 3400+ (ye i kno its old.. but couldnt afford upgrades), alongside 1.5GB of RAM (DDR cant remember Mhz), Nvidia 6800 Ultra, and the rest is irrelevant i think.

So now am thinking, is it worth purchasing a Penryn (Q6600, Q9450) or wait till Nehalem is out and purchase that. Am setting up a whole new pc (cept optical drives and hard drives), but other than that am buying new PSU, Mobo, CPU, Heatsinks (thinking of water-cooling btw), GPU (thinking of x2 ATi 4870), RAM (DDR3 maybe?) etc.

need your suggestions.. tnx in advance

Buy a computer now so you can play games until september. When school starts it won't be a good time to be playing games. And Nehalem will be expensive when it comes out.

well.. school gaming and going out is all together :P

any ideas of the price range? 400-500$ or more?