I like to sit online on the right side of the screen. For some reason I get better cards when I sit there. In tourneys/freerolls you don't have a choice tho.
Playing live - I like to sit where I can see the cards! I'd love sitting directily in front of the dealer, but I usually sit on the sides. I think I need glasses!
Holdem - sitting next to the cute dealer is fine, but they change like every 30 minutes or so, so you never know who is coming next. LOL
And I agree with Diablo - hate sitting next to smoker directly. I don't mind the smoke in the room but when the guy next to me blows it in my face, YUCK! Then there's the two big 250 lb guys on either side of me squooshed in the middle trying to reach my cards between a 6" space. LOL. And then there's the obnoxious, big mouth know it all lady (I said lady, not man LOL).... I could go on. Luckily, lately I've sat at fairly good tables that are round so it really doesn't matter the place you sit, you can see everyone.