i3 this will last you a good ~4 years w/o any problems and it is a better choice in every possible respect.
However get a Q6700 if you just want your PC to last another ~2 years w/o any hiccups. You won't be able to get it so easily though its out of stock in just about every place I've looked. In fact if you find a new one tell me, I'd buy it in a heartbeat
(It is a key component which has been missing from my old project for a while it'll be nice to have it finished after all this time)
If you do choose to look for a Q6700 though, there are a few things to look out for when you're buying. If its
new and under 7-8k go for it. If it is anything above 8k just buy a i3. And whatever you do just
don't buy a 2nd hand Q6700, anyone who had the brains to buy it back when it came out must have overclocked it at some point therefore it'll be a useless waste of money and a huge risk investing into something which has (1) No warranty (2) Might not work at all (3) Might not last as long as you might think.