You wouldn't need to be swapping parts out every couple of months with an i5 or Phenom 2 chip, the only thing that would need swapping out in the forseeable future would be the video card and that's a 2 minute job.
Hell even a Q6600 clocked at a decent speed is more than enough for games at the moment!
As for a decent air cooler there's a few to choose from, the ThermoLab Baram CPU Cooler has good feedback on these forums as well as the Prolimatech Megahalems.
The Corsair H50 watercooling unit is also good although you'll have to adjust your case fan orientations to use this.
All of the above should help you achieve 4GHz for the core i7 920
Hell even a Q6600 clocked at a decent speed is more than enough for games at the moment!
As for a decent air cooler there's a few to choose from, the ThermoLab Baram CPU Cooler has good feedback on these forums as well as the Prolimatech Megahalems.
The Corsair H50 watercooling unit is also good although you'll have to adjust your case fan orientations to use this.
All of the above should help you achieve 4GHz for the core i7 920
