I've used the Victorinox daypacks. I got them on sale at REI. They look "normal" and they have nice compartments in the front. I use the daypack from this set:
http://www.rei.com/online/store/ProductD...gory_rn=4501712

my friends have used the St.Moritz or the Geneva, also from REI and on sale for about 30. I've found these packs are more padded than I really like. These bags seem to do great even with heavy use (I took mine to Europe and abused it, came home, washed it, and it looked new again). They scream "student" not "survival".