Only PokerRoom. All the graphics and the fact that the avatars stay the same as people come and go really gave me a hard time when I first started there. I also think it was/is more of an issue because the colors of the backgrounds, "name boxes", and text are all similar, so if the avatar doesn't change and the text saying its a different person doesn't jump out at you, you are playing someone else on your previous read of another player. Never a good idea.
Just takes some getting used to. Maybe i'll get some sticky notes out and write names on them
What site are you asking about? Do you have issues with one?