Yeah, I've already heard from numerous people that RDM is pretty good at the beginning of the game, but once you get to the higher lvls (above 20) that changes.

As far as advance jobs go, I was thinking SMR Subbing NIN.

I like the abilities the NIN gets, and I've heard/read that, even though SMR are completely gear-reliant, they can perform better in big bursts, where as going for a long period of time can wear them down faster. I haven't heard too much about DRKs other than they are really good tanks and are pretty strong.

Changing Classes. At the start of the game, after you pick your main Job, can you go to the nomad moogles and change to one of the other six Jobs as soon as you start the game? Or do you have to get the other six starting jobs before you can switch to them?