Used old high-tech? or middle of the line new?

I have around ~$250 to spend on a mb and processor. I already have a case, power supply, and video card. Should I buy something used? like a core 2 quad? or zeon? Or should I buy a new i3 or i5? Also, what generally seems to be the most reliable motherboard?

Thanks.

I'd say buy the new if you can afford it since its usually better than the old in terms of technology at least.

Depends on how much you can buy the c2q and mobo for. The i3 will be more powerful than the core 2 quad.

Basically, old high-end stuff will only equal (depending on the age, I'm talking one generation older) the performance of the modern mid-range stuff. It will also use significantly more power, and probably cost as much, if not significantly more (unless it is second-hand, as older unused hardware tends to keep its value).