ive put sooooo many hours into oblivion..but let me explain.. i had my first character... eventually started duping stuff and it lost all its fun so i made another account on xbox and played on it, got tired made another game on first account, then made another account after that one cas i had taken a break from oblivion... now..... i probably put 50-70 hours in each playthough.. i ALWAYS did the mages and thefts and assassins guild... on the last playthrough i didnt finish each of them though.. and on the last one (my "main" playthrough" ) i never leveled up much... i did it all at once... i dont remember the levels but i went from 5-10ish to 20-30ish ... suddenly the gear from people i killed in quest was giving me 20-30k each invotiory i sold... all my "good" equipement was bad.. but it took a little bit to get some again...so.. did i miss something inbetween .. im starting to play through morrowind so im probably going to be a while before playing oblivion again.. but im planing to play through both morrowind and oblivion before skyrim comes out

i feel like you missed basic english

I guess it just depends on how you like to play - maybe go harcore role play next time: useful suggestions for this are on the wiki, as I'm sure you know...! Maybe putting a few rules around how your character behaves might help - I've recently stopped looting for armour, so I don't get the money there, and have to sell scrolls or do paid quests to get money....

Other idea would be to not do any main questlines, only do mages as far as getting access to the uni for enchanting etc... and then go from town to town doing quests along the way.... be a wanderer for a time, just living in the wilderness??

Roleplay

I play a pure Magicka based character and have totaled up about 300+ hours on this character so far. I have explored all of the Aylied Ruins and even I have to go back every now and then to check if I have missed something. (Sabarel likes to be very viglant in making sure she has everything that is of use to her studies.)

My main play through I've only done the Mages Guild, Fighters Guild, NoTN, all the quests in and around the Imperial City and the main story line as far as joining the Blades along with all of the DLC and houses.

As regards to what I loot I try to only take things that would be of use to my character such as Scrolls, Reagents, Books, Soul Gems and Potions. Everything else I just leave lying there still for some other scavenger to take.

You said you have done the Mages/Thief Guilds and the Dark Brotherhood, I don't know if you have tried doing the Fighters Guild or even tried to do some of the Aylied based quests? (MASSIVE Lore fan am afraid) Even spending some time going round and closing all of the Oblivion gates that open randomly across the land can be fun and each one is always different I find.

There is always loads more things to do I find. Sabarel has a very long list of things that she wants to do but Gyai (Her Black Stalion) can only carry so much at once.

If you rushed through the game like you rushed through that post, I don't doubt that you missed lots of things.

Slow down. Breathe. Relax. Don't push to get to this level or finish that quest line. Just pay attention to the character and the world and take your time and see the sights. Actually live in the world instead of just rushing through the game. There's no time limit. You can't "win." There's no 100% completion. It's just a great big alternate world and you can follow a character who's living in it. Just look at it that way and you're far less likely to "miss" anything. Or maybe more to the point, far less likely to care.

On my main character I completed the main quest, all the guilds, the brotherhood, the
arena not much to miss here as far as story, the KoTN, shivering isles, and every single
misc quest in the game. This took quite a while to do, but it was fun and I also explored
every single location in the game. I will add that exploration is a lot more fun in Morrowind,
because there is not a fast travel option.

i dont really feel like i "rushed" through the game.. when i played.. i just played.. now i did a some points rush.. like say.. i wanted to get through all the theifs guild for the mask when ive done the quest 3 time becaue of diffrent playthroughs... same for some of the others.. i did do some side quest and stuff though. i over all dont think i rushed.. what i ment was by doing all my level ups at once.. jumping from having easy creatcures to fight to having the highest did i miss alot between them though i would have gotten by leveling up as i went

I did the same actually. Got my butt handed to me by a troll just outside Imperial City and thought I′d train Lothran and level him up a bit, too many levels in fact. Now of course I know that was a mistake but it′s not the end of the world. He still lives and breathes in Cyrodiil and is happy to be alive

Gear and critters get upgraded roughly every 4-5 levels up to level 25-30.

x20 this is not just a videogame, it's a world.