Since I played Oblivion for years Vanilla now (First PC, then 360, and now back on PC) I wonder, what is the best Overhaul mod, that gives a different experience, not neccesery playwise (don't bother that to much), but like new quests added stuff/changed etc etc etc
http://www.gamesas.com/index.php?/topic/1228802-relz-oscuros-oblivion-overhaul-133/ It alters a lot so I'd strongly advise you to read the linked PDF to see if it taylors what your looking for.