I actually find it gets better every day!
Maybe that's because I'm excited to start a new character though. Up till now I only played a destruction mage (lvl 43 ~80 hrs), and while the quests are still fun, I found the combat to be a little boring. Hopefully my new archer/sneak will be more fun (so far so good!).
I also am going to do some different "main" quest lines. Like, you know, actually do the main quest. And actually start the rebellion quest. And joining the thieves guild. And finish the dark brotherhood quests.
Yeah... I did a lot of random quests on my mage lol.
Actually now that I stop and consider it. 80 hours already. For me, that's a record. I haven't put that many hours into a game in a long, long time. Probably not since Demon's Souls. Next closest is probably Fallout NV last year, but I think I'm only at around 60 and even that took months as I'd get bored and go on hiatus.
Considering how excited I am to get back on my new character... yeah. For me, GOTY. Although that's greatly thanks to the modders and their wonderful work.