I may have mentioned this already, but I am just got by this EF 70-200mm f/4L IS. It focuses fast and it's crazy sharp.
I got my copy from Roberts Camera for a bit over four hundo. It was graded "Good", didn't have the hood or the padded case, and only has some light wear marks on the lens barrel here and there. Used ones at Amazon seem to start just under five bills. New ones seem to sticker for right around a grand, but considering what the f/2.8L alternative costs, that's a deal. This is a lot of glass for the dough; one of the best bangs for the buck in the L-line of pro lenses.
.
