1) Lock and key (not digital lock pls) for your cupboard
2) 5 X clothing hangers (just need a 2 for your No. 3 and the others for hanging dirty stuff if need arises)
3) Air Freshener (not REALLY needed, but some cupboards can stink to the high heavens)
4) Toiletries (what you normally use is enough, i know some who don't even bring shampoo!!)
5) Enough underwear to last you 5 days (don't think you want to bother washing any for such a short stay)
6) Some $1 coins for the vending machine
7) A spare handphone battery, the NO CHARGERS in bunks rule applies to you guys as well (or don't use your handphone! its only 5 days!)

Food if you so wish, stored in an airtight container. And only dry food, don't bring your mother's chicken curry and hope for a microwave to heat it up... speaking of which, the no pork rule should apply as well.
9) Book/Magazine to entertain yourself with (book.. not BOOKS... you still have a duffel bag to carry home and i don't think you want to weigh yourself down with an Encyclopaedia)
10) any medications which you might possibly need due to any pre-existing conditions (and if you need any refrigerated such as insulin, tell your PS/PC on arrival and not bring a fridge or a 10 kilo block of ice)
11) Slippers for going to the bathroom in
12) A set of shorts and shirt to sleep in if you want. Some use their PT kit, some sleep naked. Whatever rocks your boat.
13) Discman/MD player if you want, portable radios are good as long as your bunkmates don't mind.
14) Perm marker, you may want to label some of your things in case it gets lost or your "friendly" bunkmates decides to pinch them.
That's all i can think of at the moment, if i can think of more i will add on (sorry not listed in order!!). You will
NOT be doing any phyiscal activity whatsoever, not even pushups or any running/swimming. (everyone is too afraid of a BOI in case some idiot slips and hurts his/her fingernail) Everything else will and should be provided and they will generally give you more items than you need in your NS life.
In general, you will be issued with 3 sets of No. 3 and 2 sets of PT kit. You will bring everything home on the last day and report to your parent unit on the following monday (you will be informed on this before you leave of course). Now, check with the Orientation Officer (OO) on the last day to see if your parent unit is a stay in camp or not. If it is stay in (yes, that sometimes can happen even for Pes E personnel), then bring your duffel bag along with you on the following monday. The sight of some goondus lugging their duffel bags up the hill in Mindef is quite entertaining! (for ppl watching, not so for you of course.)
Hope the info helps, when you going to enlist again?
P.S. oh yar... almost forgot this section
Prohibited items
camera phone
chargers of any sorts.. hp, battery etc (previously mentioned)
porn
pirated cds/vcds
camera these rules obviously still apply to you.