The Daily Grind: Games that should be MMOs?

We all have a list of favourite games which we think should be MMOs. My first real exposure to RPGs was The Elder Scrolls IV: Oblivion. I absolutely love this game and it's top of my list of titles (or in this case a franchise) which needs to be turned into an MMO ASAP. Logically (and as a games journalist) I know it's not that simple. I've interviewed several folks at Bethesda over the years and I know that their vision of The Elder Scrolls wouldn't translate too well to a Massively Multiplayer Online game.

But that aside, I'm pretty sure most gamers are stoked that Star Wars: Knights of the Old Republic is being reinvented as an MMO. I want to know, if graphics, dev wishes and game mechanics weren't an issue, what games would you like to see become an MMO and why?