With so many options, why would you not want to level another class?

I'm needed as a healer most of the time, so that's what I call my main; though depending on the mechanics I'll switch between SCH (89) and WHM (83). I run maps, Crystal Tower and just general content with my MNK (84), because it's fun to play and a nice break from my healers; not to mention it's almost as well geared as them now, so I can even do end-game content with it.

I have a WAR (73), but I don't play it much. It's nice to have a tanking class though, as I can help people out with things if they're ever in need. I also go to Crystal Tower with my tank, so that my tanking friend has dibs on all the loot.

Right before the patch I just finished leveling my BLM to 50 and I'm having a blast. I plan to do my Relic quest for it later on today with the Company. Honestly, I love leveling other classes and love that you can switch between them at the click of a button.