The_Healer said:
If it costs as much as the 5970, then there is half my budget blown in one go.
Also, on the benchmark front, the 480 seems to be topping everything out at the moment. It even beats the 5970 in a fair few situations. I'm leaning towards it.
2 more sets of benches/reviews at Anandtech [http://www.tomshardware.com/reviews/geforce-gtx-480,2585.html]. According to the Tom's Hardware review launch price in the US will be around $500, compared to the ~$400 we pay for a 5870. If you end up getting one of the GTX 400s, make sure you have a well-ventilated case and reliable power supply as they're very hot and power hungry. IMO the most compelling reason to wait for Fermi availability is the possibility of a 5870 price drop.
For cases: Antec's 900 is a good mid-tower, as is their cheaper 300. If you're considering full towers, the Cooler Master HAF 932 is great to work with and keeps everything cool.
CPU: For a single-GPU gaming system, any i7 is overkill. An i5 750 will give virtually identical gaming performance. i7 makes more sense once you get into SLI or Crossfire builds that need the X58 platform's extra PCI-e bandwidth. 6 gigs (i7) or 4 (i5) is plenty for 64-bit gaming. If you're into video or audio editing, however, an i7 with piles of RAM is more sensible.
Power: 750w is more than enough, even for an OC'd i7 and GTX 480. You could drop down to 650 with no ill effects. Good brands include Corsair, SeaSonic, BFG Tech, PC Power and Cooling, and Antec. Some companies overstate the wattage their supplies produce, so check total amperage on the +12V rails.