Disobey Gravity

Now I've finally learned how to tie in with a rethreaded figure-of-eight, belay, etc., it has occurred to me that at some point I may need to buy a harness.

So, what should I know, people? What are the questions to consider? What should I take into account (other than "it should fit me and be appropriate for a lot of indoor top-roping")? Advise me!