The only bugs I've run into are a few random crash bugs, a texture glitch bug, and a few minor easily ignorable glitches.
Although there was one really strange bug that caused quite a lot of chaos...
I arrived in Riften to do continue on with the thieves guild questline when all of a sudden a guard begins fighting a beggar and then, after he killed the beggar, he began attacking me for no reason. (I didn't have a bounty)
This of course caused all the guard I run past to attack me and I end up sprinting through the town with almost all the town guard chasing me.
Hoping to lose them, I entered the Inn and hid under the stairs when, sure enough, they charged through the door.
That's not it though, they began attacking EVERYONE in the Inn. The innkeeper, the random people in the in, that fighter lady.
Seeing this I ducked into the basement and waited behind a corner with my bow drawn. After a while, a few people had died and the guards begin running down the stairs only to have me pick them off one at a time. (Giving me a 2000 septim bounty)
In the end there were a pile of dead guards in the basement and 3 citizens had died, including the innkeeper. Then, when I went outside, I immediately found that all but one or two of the guards had been killed and I proceeded to bribe a guard 1000 septims to clear my bounty.
I never found out why that guard attacked me...