I like tank and Healer but thats just because I feel they keep the pt alive by either taking all the hits, or healing the guys that take damage!

DPS is fun though, running around, dodging AoE's hitting from flanks to rears! lol

In other words no matter what class/job you choose I'm sure you will enjoy it to its fullest

Thankfully (as far as i know) there is not a "better/needed above all others" class

So have fun!