My Fuji S2 doesn't have a compressed RAW setting, and I get 77 shots per 1G card. Jpegs are about 1/3 the size - I think it's 208 per 1G card for native 6mp size, fine setting. Jpeg file sizes vary a little from shot to shot depending on what's in the shot, but it doesn't really affect how many I can get on a card.

Best way to find out is to put a 1G card in the camera, format it and see how many will fit of either format.