Sorry for the rant below but I want an answer on this.
Ok here's the deal, Ive been playing Skyrim since february and I have 2 characters : a lvl 43 Khajiit assasin/thief and a lvl 29 Nord warrior who also took the role of the dragonborn ( my khajiit isnt interested on that, just the loot and gold

Now I don't rush anything in Skyrim, ive been playing very very slow, roleplaying, doing quests at my own pace (im halfway finished on the main dragonborn quest on my nord warrior) and ive finished the companions quests.
On my Khajiit im at the beggining of the Stormcloak quests and ive just received my first quest in the Thiefs guilds (haven't joined the Dark Brotherhood yet but I plan to) .
Now the question :
Is there enough to keep you playing Skyrim after you finish all the guild quests , main quest and faction quests?
Also about the Radiant quest system, does it add just miscellanous quests like : fetch that, kill this, deliver that?
Thanks and sorry for rambling