My game runs perfectly fine as well.
I have an 80GB fat model PS3 with an upgraded 320GB HDD.
I'm level 13, 30 hours into the game with a save file of 4,4MB so far that does increase.
I've done some quests and have a bucket load more in my quest log. I've killed a dragon (apart from the scripted first one) and also encountered another one that didn't attack and left.
I have roamed in and around of Riverwood, Whiterun, Falkeark and Riften on horse without problems.
I have played for more than 4 hours straight. In fact I tend to leave the game running when I take a break and go back to it later.
I have the 2.0 update installed (which oddly doesn't have a sticky thread yet).
I feel blessed

for not having problems so far and I hope it stays that way.