CF Cards

Hello. I am kinda new to the 7D and have yet to go on a long ( ish ) trip with it. I searched how many pictures you can get on a CD card. Trouble is I don't really know how many pictures I would take. I tend to shoot in RAW, but I could shoot in Jpeg I guess. I am going to Vancouver Island for 4 days. I already have 2 x 8 G CF cards. I am worried just by the size of the RAW files that won't be enough. I know this is on a person by person basis and hard to answer but how many CF cards would you take? I tend to take allot of pictures. CF cards happen to be on sale right now and I can get a 60mb/s UDMA 16 G for $79.99 or a 32 G for $149 ( sandisk ). Which would you buy, if either. Thank you.