I've had quite a few bugs - the visual ones don't bother me much. Sure, I saw odd dragons and guards hovering over the Riften Canol and such oddities - but that is funny, not game-breaking.
Game-breaking for me is that my main char can't finish numerous quests due to stuff I can't control or had no way of knowing at the time. Her quest log is crowded with stuff I can do nothing about.
"Return to the Jarl of Riften" is one - she said she wanted to make me Thane once I bought and visited my house. -But she doesn't. Tried handing Riften to the Imperials on a silver platter - doesn't help. Still no Thane-title.
-- Solution: Talk to the Jarl BEFORE visiting your new home, once you bought it. -No damn way I could have known THAT to start with - so no Thane-title in my favorite city for me. I found no solution to this one - stuck in quest log forever.
"Visit the College in Winterhold" - Yups, I did that. -I even became Arch-Mage, on my THIEF no less, trying to get that silly objective done! Nope, quest log still tells me to visit the College - probably due to a random dragon attacking while I was being showed around on my initial tour, causing my tour-guide (forgot her name) to bug out and refuse to speak to me. I managed to get the quest to continue by simply moving to next part (Attend first lesson), but yeps - I am Arch-Mage, and yet I apparantly never "Visited the College of Winterhold".
"Collect Bounty from (Insert former Steward here)" - Make sure to do ALL bounty-quests before advancing the civil war. I didn't - that was stupid. The new steward will NOT hand you a bounty for what the old steward sent you off to kill, and you are stuck with yet another misc. objective in quest log that you can't do.
Hjerim - the house in Windhelm.... ARRRRRGH!!!! -Need I say more? My main character never triggered the initial quest, and hours on the net trying to figure out how to bypass it was to no avail for quite a while. See the threads about it in this forum. so - damn - annoying! I got the house now by cheating with console commands, but never use it due to bugged lighting etc. - and I also had to remove various mess + old furniture manually by using console commands.... Not good enough

-And there's more... that I can't remember right now. My char is getting old now, I had her since I got Skyrim a few days after launch, when things couldn't just be foreseen by looking at the wiki every time. Some day, I will try making a new char, and try and "do it right" to hopefully resist the worst bugs - but it will probably be when my main is done, I tired of Skyrim, played something else for some months or a year, and THEN return, if ever.
Hopefully, by then, most of these bugs will have been fixed anyway, and someone clever will have made the otherwise useless thieves in Thieves' Guild into marriageable characters after one becomes Guild Master - just like in The Companions when their quests are done
