blackmage/whitemage for training, blm/nin for early petcamps, blm/rdm when u get higher in levels.
If you want to focus on damage just be sure to keep your elemental magic skill capped each level and eat lots of melon pies, while focussing on as much +int as possible in your nukeing gear until you get to higher levels.
Now, I quit the game a while ago but I was leveling blm when I did and I can say with confidence that, depending on race, cream puffs are superior to melon pies for soloing. That 3(2 for the +1) difference can literally mean the difference between one shotting and having to cast again, potentially losing the exp. chain. Obviously this is when you get access to Ancient Magic so disregard this for pre-AM levels.
First post in a while so hopefully this helps. And to Delfi, I'm not calling you wrong or anything. I'm just offering different advice that could save the OP some unneeded frustration.
Edit: Also, something else that cream puffs have over melon pies is the -10 HP. This helps, ever so slightly, proc your Sorc. ring, should you have one. Less of a threshold to overcome. It's only 10 but every little bit helps if you're a non-taru. Edited, May 14th 2011 10:27pm by XxHigetsuxX