Well, my first piece of advice is to not spend $300 on a Q6700. If you want, I would get a used, known OCing Q6600 or Q6700. I am not positive about the Q6700's, but the newer Q6600's are of a lesser VID and tend to OC poorly compared to older versions.
If you are not OCing or don't want to go used, well, I would save and go i7. (you can also go with a wolfdale quad. Q9550 is a decent performaer and OCs nicely)
If you are not OCing or don't want to go used, well, I would save and go i7. (you can also go with a wolfdale quad. Q9550 is a decent performaer and OCs nicely)