Best place to sell used Lenses

I just upgraded from my Canon 50D to a 5D MKll and need some advice on the best place to sell used lenses......at a fair price.

I'm hoping to sell my EF-S lenses to help fund the EF 135 2.0L I recently purchased....if I can get a fair price. I'm actually considering keeping the 50D, but will use my EF lenses if so.

I recently sold a Tokina 12-24 on Craigslist (in Atlanta) for close to what I paid for it 2 yrs ago. So, that's definitely one possible avenue.

I'm hoping to get some recommendations for some other good places to sell used lenses.

Thanks