Mostly sitter, apart from some toilet breaks. When my opponent is thinking for a long time, I walk around a bit.
Especially when he thinks more than fifteen minutes, thinking even longer isn't going to make him find a better move. Opponents often force themselves to come to a decision the moment I sit down again - so in that case I'll keep on walking until he makes a move :-)
Well I've just been to my first otb tourney found out that I am a sitter, couple of times I stand up to get a better view of the board is has been a little weird for me because i am so used to 2-D so I haven't played on the board for a long time. I have question though is it impolite to make a move while standing, do you ever do it ?