I'm not promoting Q6600, but Q6600 is known aside from its fast 2,4 Ghz speed, is also known as the easiest one for overclocking, since Q6600 possesses bigger multipliers than its similar friends, causing it to have overclocking performance as high as Intel Extreme series processors (ex. QX6600, QX others).
Because of that also, Q6600 is known for its great stability even when running under overclocking conditions.
I estimate Q6600 will still last you 3 years from now, if not more( Apps just need more RAM in the future, not much regarding processing power). Considering its very cheap price, it's worth it.
Read my topic on why go for core i series, See i estimated the same thing what a war,lol