Honestly I'm suprised so many people said Summoning, i've never seen the point of it.
I usually mainly play as your standard Robin Hood-type, Bow as main, Sword for close-quarters, stealth and what-not, but every now and again i made a mage who was only allowed to use magic, no weapons beyond his fists(although he eventually found a magic sword in one of the various ruins and used that, but his Blade skill sucked so it was mainly a last resort deal).
I haven't played Oblivion in awhile, maybe i should again, see what this Summoning buisness is about..