Colin Carron , Jan 20, 2009; 09:05 a.m.
I depends to some extent what camera you have. The larger the pixel count on your camera the fewer shots you can get on your card. It also depnds on how trigger happy you are. I tend to bracket shots quite a bit especially if I think it looks good.
Taking large jpg and RAW I would expect to fill 2GB to 4GB a day on average using my 12 MP Canon 5D.