I am not trying to imply that the 70-200mm F2.8L IS is not a great lens. It just seems everyone raves about the F4L IS and I know mine is very sharp. It is probably a mental block more than anything. It seems like getting rid of the F4L IS, paying an extra $800 and getting a lens that may be lower in IQ, even if it is on paper, is strange. It is a personal thing. I know if I get the F2.8L, I will want to use it in other applications where I would wish I had gotten the F2.8L IS.
I can just see the future. I started with the 70-200mm F4L, went to the 70-200 F4L IS, now thinking about the 70-200mm F2.8L and eventually it will be the 70-200mm F2.8L IS. I am thinking I should just skip the middle man.

Canon EOS 7D with BG-E7 battery grip, EOS 40D with BG-E2 battery grip, Canon 20D, Canon EF 70-200mm F2.8L IS, Canon EF 24-70mm F2.8[COLOR=#ff0000]L, EF 300mm F4L IS, EF 400mm F5.6L, EF-S 17-40mm F4.0L, Canon Speedlite 580EX