I'm interested in finding some mods to get for it. I do, however, recommend Qarl's texture III mod. It's insane and like quadruples the texture quality.
And the unofficial Oblivion patch. It fixes around 2700 bugs.
I love that texture mod, makes my oblivion feel a little bit more realistic
Mods that I can reccomend after playing it for about a few weeks now are -
For Castles, I think
Castle Seaview or
Castle Almgard is a great choice.
Glenvar Castle has a quest to it but it's just too empty to me and the quest is not that fun. If you like the original Battlehorn Castle then get
Battlehorn Castle Enhanced. Get
ImpeReal Castles to make castles in cities a lot better
Streamline is a great mod if your computer is having lag problems, or if you want to do a texture pack on high settings
For weapons,
Adonnays Elven Weaponry is awesome and so are all of the
Realswords mods
Armor-wise, there aren't too many lore-accurate sets out there, I personally like the
Dread Knight Armor, and the
Blades Ceremonial Armor. If you're not going for lore then
Sauron's Armor,
Gondorian Rangers Gear,
Lich King Armor and
Frostmourne, and
Ringwraith Armor is all cool.
For dungeons, if you liked WoW then
Scarlet Monastery is really well done, I bet you'll like it even if you have no clue what WoW is.
Other mods I like are
Kvatch Rebuilt,
Knights of the Nine Revelations, and
Midas Magic.