Hmm. This used to be easy, but it actually depends on the situation (and on the game). The quick and easy (and in most cases right) answer is "Tank".
However, there are a few conditions.
One: This only applies to World of Warcraft (and to a lesser extend Star Wars Galaxies). I tried tanking in Everquest 2, Asherons Call, Asherons Call 2, Lord of the Rings Online and Dungeons and Dragon Online. The only game I really "got" it was in WoW. Star Wars Galaxies is different, because Jedi was the only tank class and melee DPS class at the same time - and it was brought on late and rubbish as well.
Two: There are days when I enjoy something mindless. Now I do not want to look down on DPS, because performing at the top of the game is obviously easily as challenging as tanking. However, if you want to do okay, you can just play around with DPS and blow some crap up. It's fun, it's quick and for me it's a lot like a one-night stand. Nothing serious, but good fun now and then.
That said... I think I enjoy melee classes vastly over ranged. I appreciate the better view from the back, but I cannot really enjoy myself there.
Oh and healing? It terrifies me. I can't do it. I mean.. that's not entirely true. I can heal, as long as nothing goes wrong (or could in Nexus at level 72 - the last time I tried). As soon as the shitteth hath hitteth the fanneth, I flounder and fail. Not going to do that again.
What makes an MMO different from WoW?
23 hours ago