I played the hell out of Fallout 3. It was such a great game, I just couldn't stop playing almost daily. Bethesda designed it so well, that if I didn't want to follow the main quest, I could just wander around the massive world of Washington DC and explore. I did just that. I played every side quest I could, and explored 95% of the massive map.
I won't spoil it for anyone by describing the ending, but will only say that it was awesome. I highly recommend this game as a completely fun RPG. I'm pretty sure this game may be the most enjoyable game I have ever played. I have to admit that I'm sad that it's over