Well, I tried to level WHM a bunch after I did that run to 30 with my BLM, and it just fell apart. I got a party that wasn't. . . . well they weren't exactly the best level 42-44s out there. That kinda disheartened me a bit, so I'm currently working on my Bard, which is 18 (would be higher but I had another hockey game last night and I'm headed out with friends today, so I'm not partying) and should be 30 within a couple days. My only worry is getting my hands on a scroll of Mage's Ballad. . . I could easily buy one, I've got the money sitting there, but I just wouldn't feel right buying it when I could quest it and not have to deal with buying and then selling another copy later once I quest it. Oh, I also got Mary's Horn. I was randomly farming and I ran across Stray Mary, completely untouched, so I killed her and got my horn, was quite a nice surprise after I threw up three times playing hockey that evening.
For the moment, I've decided that the jobs I'm going to be "actively" leveling for a while will be BRD, MNK (WAR sub), WAR (THF/PLD sub), and BLM with a touch of PLD sprinkled in because my linkshell needs another tank, currently the only one is the leader, so he has to do like. . . well. . . everything.
Of course, most of the leveling will revolve around Bard. . . I love the class, my sub job is completely leveled already, and its incredibly fast to level, so admittedly I'm going to be spending a hell of a lot more time on it than on the other 4 jobs that I'm currently looking to level.