These are the three virtual worlds I'm most familiar with. I thought I'd compare their visual style next to eachother, with a focus on Avatars. I tried to get shots with both boys and girls, fancy and plain, in each. To make things simple, I also tried to get avatars just sort of standing around. All three of these games have dance-type moves, but getting a shot of each, of comparable quality, would have been tough.
Gaia Online, but I just couldn't manage it. Needless to say, they have very cartoonish, anime style avatars that don't, strictly speaking, animate. Not terrible, but not great either.