[quote name='maximumzero']How much storage does he need? 16GB Flash Drives are fairly inexpensive and pairing two up will get you roughly 32GB of storage. (Formatted capacity less, of course)[/QUOTE]
Thumbdrives are great for adding on to the older systems, but some games (or parts of games - the Halo ones in particular) actually require an HDD. It's still better to keep at least a 20GB drive on the non-slims for that.