Webmaster has pretty much got life on a fast attack pegged.  Sodas, cigs and dip are gold, especially when trying to get qual'ed.  Only a few things I would add.  A new pillow is nice unless you like using one that smells like ass and has stains all over it(just drool if your lucky).  Also I always brought a box or two of fabric softener sheets.  I would put them under my sheets, inside my pillow case, in my bedpan and just about any other place I could think of to try to ward off(at least a little bit) the general funk of the boat.  As far as luxury items go perhaps a palm pilot with a couple of games on it would be nice while waiting on the mess decks in between training sessions and drill sets.  As for items like laptops, playstations, dvd players, etc.  I wouldn't waste the money or the precious little space you have untill you are qualified.