I am a Monk and Love it! I started out as a WHM and enjoyed if for awhile while me and my buddy (War) worked are way up to level 22. The only drawback was my innability to effectively solo (go figure, duh I'm a whm). We both tired of our jobs, me for never really getting to fight, and him for only getting to fight.
So we both decided a job change was in order. He chose RDM and I initally chose Thf (Level 15 now). Again, I was finding it hard to level solo. We typically always partied when we played so that neither would get too far ahead in terms of levels. One weekend he was unable to play, and me not wanting to get too far ahead decided I would start another job on a whim, and make some gil farming low level mobs.
I picked Monk and have never looked back. I was able to catch up to his RDM in less than a week. And from having other previous jobs (which includes BLM at lvl 12) I always had enough gil to keep my monk in the best gear availble (so far anyway). I now have monk up to level 22 and am looking forward to future levels.
If you looking for a monk to party with, give Hunley (me) a tell!!!!