I see a few people suggesting things for the "Gender You Prefer Playing" section. Perhaps to avoid potentially offending anyone who might be easily offended, an option of "Flexible" or "Adaptable" or something along that line could be added.
The Time Zone idea is pure gold, and would help players and GMs coordinate more efficiently. If it could be easily implemented, I'd say go for it. But something like that might also be a pain in the ass to code.
The Preferred RP Section (Chat, Threads, PMs) is a great idea as well. Would help players who frequent those types of RPs to find one another a little easier.
Custom Fields might not be too bad of an idea, but adding coding in could create issues with people adding images. The Resume can be seen from any post someone makes in the threads via their avatar, and adding an image into it could throw things out of whack and mess up the layout.