So you were playing Oblivion on xBox before?
Then you should maybe consider an overhaul like OOO.
You
really notice the difference if you played Oblivion the "normal" way before
Aldo get the unofficial oblivion patch! It fixes many bugs.
Other mods I really like but may not be THAT important

:
Better Cities <------Makes the citys cooler xD, for example adding carts and stuff to the market distcit
Birthsigns expanded <------birthsigns play a more important role with this mod
DarkUId DarN <------Cooler look with the menus +
better menus

Oblivion XP <-----Different lvling
Alternate Start <-----Dont have to do the toturial everytime you start a new char
QarlTP <-----WAY better textures (4 or more times better)
Toggleable Quantity Prompt <-----Get this!

Good if you wanna train mercantile
I have more but these are kinda ma favs

(I may have missed a few mods in my mod list which I find cool

)
And of course...get OBMM!!!!