Ah Hah!
nm. It's fixed. It turns out that when I copied over some fonts from my PC, I brought over LucidaGrande.ttf - which causes the fonts to go wonky in iTunes because apparently it is expecting LucidaGrande.dfont.
So all you have to do is look for any instances of LucidaGrande.ttf and delete them, and all will be well.
Sorry for being a noob.