i don't need greater protection, i'm a natural assassin(in the game that is), the dark brotherhood all the way. light leather armour. usually my vict.. er... my *opponent* doesn't see me coming, i usually use a charmeleon spell or enchant something myself. sneak up behind him/her and *bam* you get the idea.... or you could make a script to put on an arrow, which kills them slowly, just one arrow and they wither away, callaps and die... i had the script written down somewhere for morrowind, i'm sure i can make it suit oblivion, if anyone wants it.
light armour, all the way..............................
Thats the sort of guy i had with my second character so i did use light armour, but with my first character i was a warrior so i was using heavy armour.