Leveling in oblivion?

The way leveling works in Oblivion is that only your major skills affect leveling up, so with what you described, I'd pick Marksman, Blunt, Illusion, Sneak, Security, Conjuration as major skills, though you need 7 majors so pick something else that will fit what you're trying to do. You can still level the minor (leftover) skills and get the "perks" that come at 25, 50, 75 and 100, but as far as your character level increasing, you need to level up major skills 10 times to level up. I suggested the major skills I did because it sounds like you will be using those the most, and with Oblivion's leveled-loot system, you'll want to level up rather quickly to avoid getting the cheapo versions of quest rewards.