I became Arch-mage of the mage guild yesterday in Oblivion. It was a great story arch, involving a plot by the region's necromancer cult to take over the mage guild for nefarious purpose to be sure. The story ended with dramatic confrontation, me against the fiend Mannimarco, the King of Worms. It was an epic struggle involving multiple conjurations and fireballs, but I ultimately prevailed. I returned to Imperial City triumphant and, more importantly, the new Arch-mage of Cyrodiil.
Poking around the wiki for Oblivion, I stumbled upon a great collection of mods for the game. It's commonly agreed that a major failing of Oblivion is that the land's monster population scales with the player's level rather than remaining static. The designers defend this feature, citing the player's ability to visit any part of the game no matter how low or high their level. But few players like the design choice and quite a few mods exist that change that scaling by repopulating the game's landscape and dungeons with a variety of leveled mobs.
When I finish "vanilla" Shivering Isles (the game played without mods), I may just roll a new toon and give some of these mods a try.