I was going through my old collection of fantasy miniatures that I use for WFRP, and they're a bit of a motley lot - some old Mordheim, figures, some very old generic fantasy figures from who knows where - and I decided it was time to rebase them all for WFRP. Most of them are on small generic Games Worskhop square bases, but I've decided to put them all on round bases, as they're never going to see action in a tabletop Warhammer game.
At the moment I'm putting them all on Warhammer 40K-sized round bases. Larger round bases (Warmachine-sized) seem to be popular lately, but they seem a bit big to me for 28mm figures. It struck me that square bases are pretty much disappearing, except for tabletop Warhammer.
Rambling a bit I know! but what do the rest of you do - have you rebased your fantasy figures for use with roleplaying games on a standard base size? If so, which one?