I'm going to go against the tide here and say, "wear armor!" All you lose is Wis to AC, which won't be higher than 10 (plate+shield) for most if not all of your career, and some extras like Flurry of Blows.
This depends on the rest of the party. Because you're forgetting that for 750 gp, he can get 50 hours of +4 armor bonus. Yup, wand of mage armor. Even better if MIC is allowed, Eternal Wand of Mage armor. Two hours/day for 820 gp, no use limit other than the 2/day. At the very least, a rogue is confirmed, he can UMD the wand on a 20. If the indecisive player picks sorcerer, he can use either with no check. If he picks bard, he can UMD a regular wand and automatically use the eternal wand (all it requires is being an arcane caster). If you do use MIC, eventually it is worth shelling out for an eternal wand of greater mage armor (Spell Compendium spell, level 3, same deal but +6 bonus). Since that's CL 5, this will then cover you for 10 hours/day. You could also just buy up bracers of mage armor, but that's more costly and takes up a nice body slot.
Another trick: Magic Vestment (cleric 3) lets you give regular clothing an armor enhancement bonus. This is fine on its own, but ask your DM to let you enhance bracers of armor as if it were armor, so you can get bracers of armor +1 and eventually enhance it each day higher on your own. You could then use the bracers of armor to pick up nifty special abilities instead, like fortification.
Really, having a sorcerer in general (or wizard) in the party would help you tons. A Monk's unarmed strike counts as manufactured or natural, whatever's most useful for you in any situation. So the level 3 spell Greater Magic Weapon can be a huge help to circumvent the criminally overpriced Amulet of Mighty Fists (and save the slot for wisdom boosters), if you had a party member to cast it for you. Otherwise, it's also a level 4 cleric spell. Other GREAT sorc/wiz spells for buffing the monk:
Girallon's Blessing - Spell Compendium, level 3, 10 min/level. Gives some extra arms for additional attacks and all hands grow claws, allowing for rending.
Greater Mighty Wallop - Races of the Dragon (I think), Level 3, HOUR/level. This is like greater magic weapon (including a +1 min/level 1st level version), except the +1/4 CL bonus applies not to enhancement bonus, but increases the effective size of a bludgeoning weapon! Doing damage as a collosal creature is just fun.