Well, for 2 grand USD I'd look at picking up a quality motherboard (ASUS for sure) and then getting an i7 or a good intel quad core CPU. Usually the motherboard/CPU should be a good chunk of the total cost by themselves if you want an upgradable system where you won't have to worry about installing processors (by far the hardest thing to change on any computer)

I'd reccomend making the choice between ddr3 ram and sli/crossfire right away, so that you don't get stuck on upgradabiliy. If you've got a high budget you can get sli/crossfire boards, but it costs extra and it's next to useless to have both technologies. With the current budget/way the market's going, I'd recommend ddr2 with crossfire (so like an ASUS P5Q pro or deluxe as far as the motherboard goes) Right now, if you hunt for a good deal, you should be able to get 4 gigs of ddr2 ram for 40-50 dollars USD, since the price is dirt cheap. The 2x2 GB is alright, though I would say buying a couple 2 packs of 1 gb on sale would be a better option, if you could get well-speced stuff. The PSU and case that Excalibur posted are good, if you're looking at other cases Antec has some affordable ones that are quite good, I've been using a 900 for the past year and the thing is literally a giant fan.

Anyways, for the gfx, a 4870 is a great card, if you're looking to do high-end gaming (Crysis and shit) then you might consider 2 of them, or a 4870x2 if you find it for less than two 4870s. Anyways, always need to remember to get a processer fan, and to pick up an OEM (or retail) copy of a 64 bit vista OS if you want to run 4 gigs of ram. Other than that, it looks like a pretty solid system, the system that was posted earlier is on the low end of your budget so it makes some concessions, but if you bump the mobo to something nice and the processor to an i7 or quad core, you can expect a price jump of around 400, which can be pretty steep.

As for the quad core thing, it's got a shared cashe and some games will run on multiple cores, some won't. Either way, when you do run a big game, the processor will transfer other background programs to your other cores, meaning that you dont have to turn things off, and that minimizing your game won't crash your system like it did back in the single core days.

Not true, it all depends on the developer to program the games to run under multiple cores.

See: http://news.cnet.com/Game-developers-adapt-to-multicore-world/2100-1006_3-6175051.html

I have Left 4 Dead and it uses both cores on my dual core intel.

Really, the best option you could get right now is Core Duo, it's like Dual Core on steroids, and is better than quad core.

Alright, sounds like Core Duo right now right way too go. Unlike what others been telling me to buy Quad Core sigh.

I just want a pretty good gaming system to run newer games and stuff.

Since U.S is ahead in PC Technology makes it hard for Australia get somethings since not even out in Australia.

Anyway now I am just waiting for the money to come through and I should have a new pc soon enough.