You know, as someone from the retail world, I could go Core i7 and dual GTX 285s now, or just wait for 32nm cpus and 40nm gpus at the end of the year. My C2D E4300 is clocked at 3.2 gigahertz, my GTX 260 plays all my games.
If YOU have a C2D or C2Q and either a 9800 series, GTX series, or 4xxx series card, just wait. Sure you will get more FPS now with an upgrade but its not going to be a massive increase. And even if the next generation chips are just a die-shrink, they will put off much less heat and OC better. If you don't overclock, then you will be getting better cooling and performance anyway.
All I'm saying is that now is the time to wait, not buy.