I have completed the civil war, main and all the guild quests. Also all the daedric ones and practically all the side quests, I bought all homes, am thane of all holds, over 600k gold, have an armor ratting of 748(plus enchantments) have inherited in almost every business, cleared every dwemer ruin, almost every cave, and have done all the college ritual quests. Is there anything else I can do I skyrim at this point?

Get a bounty of 100k in all the holds. That'll keep you busy!

Daedric Quests? Dragon Priest Masks?

Both done...

I'm not a fan of vampirism, but you could go Stage 4 and try to stay alive in towns?

That's all on one character? Got 100 on all skills? I know some ppl do that.

Start up another character using different skill's?

Makeup a backstory for a character and follow what they would do, liveing like they were a person with the need to eat, sleep and have a "job".

practice your dragon riding skills, reverse pickpocket ALL your money on to the beggers, and just WABBAJACK WABBAJACK WABBAJACK!!!!!!

Well you said armor rating of 748... but the cap is 576. :/ And no there really isn't more you could do.

Getting lost in the woods always seems to get me somerhing new.

Get all dragon shouts?