would it be better to buy a core 2 duo @ 3ghz than to buy a core 2 quad @ 2.4 i have an average ati gpu but not sure if it would be worth getting a quad yet until i get new gpu but for the next 5 years will this upgrade even be woth it
The title is asking something completely different form the content, lol, but even a Core 2 Quad and especially a Core 2 Duo wouldn't last you 5 more years (unless all you do is browse the internet).
To answer the question in the title: Neither, for different reasons. The C2Q I already went over, and a Sandy Bridge or Ivy Bridge i5 will do all you need it to do. Even then, a current i5 will be getting a bit long in the tooth 5 years from now.