Sometimes I feel as if I haven't even scratched the surface of the game yet.

I just noticed the other day a line of ants marching across a large tree stump. It's not much, I know, but it is some nice eye candy I've never noticed in the 100's of hours I've so far played.
I'd been playing probably 150 hours before I noticed those Ants, and had I not stopped to sharpen my blade before an assassination I doubt very much I would have noticed them at all.
I'm at about 210 hours now, and only just found Meeko the dog. Had him follow me for a while, but he got killed, so I reloaded and sent him home. I might get him again, as I like dogs, but never when I go into battle. (I wish I could tell him to stay in Whiterun, he'd like it there.)
And amazingly, I've only just met Puurtharnax (sp?) as well. That was a long-winded first meeting...it was just before dawn when I made it up to the Throat of the World, and easily gone lunch by the time he'd stopped talking. (In-game hours I'm talking about of course.)
Still amazes me really when I'm finding new things after playing for so long. Gripes aside, this is by far the best game I've ever played.