i've never played a pure Warrior in any Elder Scrolls game. I don't know why, it's never really appealed to me. Now, Mages and Sneaky types are where I have the most fun. However, I have extensively played and enjoyed Spellsword-type characters in the past.
I find the different ways you're forced to fight with these types of characters to be more entertaining. I love nothing more than eliminating an entire dungeon without being spotted, or (even better) sneaking to the bottom of a dungeon, and then back out without engaging in combat.
That said, I've recently bought the two expansions, and I feel Knights Of The Nine will warrant a Paladin or Crusader (both classes I've never tried).
Another way to breath new life into the game is to change your chars "alignment" (it's a lot more than the simple D&D style for me, but it serves to describe in brief). If you mainly play evil characters, try a do-gooder. I did this after many Assassins, Nightblades and mean Mage-y types, and I've not gone back to playing the darker side of Oblivion!
Edit: My current character is a pure Thief, for now. They always tend to develop and change for me. That's what keeps me coming back.