Skyrim on the PC - holy moly, I have a hard time pulling myself away from this one. I'm currently lvl 48 and have gone through (I think) most of the storyline, but I keep finding interesting things to do. I've never played a game quite like this before.
Final Fantasy IX (PS1) - I haven't played though this in years (8 or 9) and it's been a blast playing through it again with my 5yr old. He's been gripped to the story, which has kept me going, though he's not a big fan of the grinding. Which I do a lot of. We're currently nearly 50 hrs into it and (I think) about to hit disc 4.