I want the EF 800mm f/5.6L IS. No idea what I'd do with it, but it would be so cool to have. Football and soccer I guess. I'd have to get into birding and moon shots.
Just to have? Probably the 300 f/2.8L IS. I have the 85L, which would likely have been it several months ago. I could definitely use the 200 f/2, but the 300 f/2.8 would be great...takes a 1.4x and 2x TC beautifully, giving a 420mm f/4 IS and a 600mm f/5.6 IS all in one.
I've got about everything I need. If there was ever another lens I'd like to have it'd probably be the 500/4. I can do almost anything with the 300 + 1.4 converter but the 500 would give me a bit more reach for sports like motorbikes and surfing. I reckon it would be difficult to use though. On a cost/use basis it's not really justifiable for me so I'm unlikely to ever buy one.
It is the last lens for my setup that I have a practical use for, could extend its use with 1.4 and even 2x extenders. I have to save up for this one, so it will take me some time
I have a few Ls, a lot of non L's but am covered for the range I shoot. I love my 45 TSe and would buy a 24 TSe--that's probably the only L I would like now--maybe the 35 f/1.4L since that's in my favorite FL range.
