Most of the mods I can recommend are ones that almost everyone else will, but i'll post them anyway.
KotOR:
Brotherhood of Shadow
WotOR
New Soldier Clothing
Bastila on Korriban
and
TSL:
Force Fashion
Combat Suit Replacement
Final Touch [Though admittedly, I only use the lightsaber models]
Bodies Stay
These are my top 4 mods for both games.
[I tend to stay away from things like USM, as there's not really enough time to collect anything.]