The Elder Scrolls line is probably the best RPG series for the PC.
As far as MMORPGs go, I was able to beta test the LOTR game, and it was pretty decent.
My preference is EQ2. The graphics are nicer than WoWs, but requires a higher end machine to see them in their full glory. That's the one the Mrs. and I play together.
I've played WoW, SWG, EQ2 and beta'd D&D Online, LOTR, and Vanguard. EQ2 is still my favorite.