I asked the question of publishers over at theRPGsite as to which design software they used, and this thread resulted. Its a good read, and folks have some nice recommendations on the expensive, professional stuff down to tricks with freeware (the latter definitely being more in my budget). Check it out if you've ever had aspirations to release your gaming products, or even want a nice presentation of homebrew stuff. The publishers over there are also really great when it comes to answering questions openly and directly.
(If that doesn't interest you, there is this thread, where people come up with various ways [in jest] they are the "old-schoolest").