In Vanilla, I was a priest, but knew very little of what I was doing.
In TBC, I was a hunter, and a good one.
In WOTLK, I have been a druid - an awesome druid!
Now, initially one would think that I would switch to another class for Cataclysm. However, i doubt that will happen. Ive immensed myself into the druid class much more than i have ever previously done with either class, and my druid does offer four different ways to play the game if i find myself bored.
That being said, i love being a moonkin. I doubt I would spec to anything else, especially with the awesome changes coming along. Shroomkin all the way!