As for building a 5+ year system, here's a rough visual representation of why this is a bad idea.

As you can see you are really paying through the nose for those last few FPS that you're not going to get with a $1000 system. But! Buying more often for a more reasonable price yields better results since that $1000 system the next year will trounce that $3000 system, and probably have more features and options. Plus you're getting a new warranty as well.



Uploaded with ImageShack.us