Hmm, if it was me...
the whole series of the Kx00/x01 frame bores me to tears, so they'd be out. They look great, they're comfy, they even sound great, in a boring way. The K1000 are such an obvious choice that I'd almost lean away from it, and as long as I had good speakers around I doubt I'd miss them too much. All the reports of muddiness and "musicality" of the dual-driver AKGs would lead me to want to strike the K280/290 as well. But then 3 versions of the K240 would be a little too similar to one another as choices.
So, in the end I'd go K241, Sextett, and K290.
Predictions for Fitz: one sextett, we know. I'm betting the K290 is in there as well, he loves those things. Finally, I believe the K401 is his favorite version of that frame, so it's either that or the K1000. Am I in the ballpark, Fitz?