the main story has some nice quests, altough one confused me a lot!
If you don't want to go through the recemendation quests you can use a mod, but it obliosly breakes all the recemendation quests. other mages guild quest should work as normal.
And i remember now, if you want to join every guild, the easiest way is to become leader of the mages guild and then do the thieves guild quests.
EDIT: is there a way to train your blade/blunt/handtohand skill on ally's? In the fighters guild they sometimes fight eachoter, and it would be cool if we could challenge someone for a friendly competition. (i know you can just attack some one and then surrender, and i also know you can use summons as dummy's)