Probably one of the reasons we keep the UO accounts open, or as in my case, we let them close for one month, reopen them, etc. is the house decay system.
Also, that UO (at least for me) was my first MMORPG. And it is impossible to recapture the 'events' that a newbie to MMORPGs feels when he enters this world. Then we are always trying to recapture it in other games, but it is not the same.

About hattrick: I played it 2-3 years ago. First year I was 3rd, playing regularly, learning. Second year I made the team the first day, and never logged back in until I got the "your account will be deleted message" many games later. End result... 3rd! The 3rd year I was 3rd too doing NOTHING AT ALL. Then I decided the game was worthless, at least for me. I must say I'm not into soccer. I know the results of the games, which is impossible not to in Spain, but that's it. When we go to a pub and they have a game on TV, my friends are happy with me, as I'm the one who takes the seat with the back to the TV...

Darkfall, that shows promise!

Age of Conan: waiting for it! But will need new computer. With Vista (Argh!!!)