It's best for me if I don't play ANY MMOs for now.
If I tried to do that to settle my Runescape urges it'd be like trading crack for weed. One addiction for another, then I'd have the same problem just with a better game.
Also, I actually knew somebody who "moved on" to WoW but occasionally came back to Runescape, because he simply wanted to play it some more. And I've quit Runescape since August, I'm just trying to stay quit.