Laying out RPG books with word processors was starting to drive me crazy. I started out using WordPerfect 10, but for some reason my version was producing a disturbing number of corrupted files and strange errors. The program itself may not have been responsible for this, but I switched over to OpenOffice anyway. OpenOffice is a very nice product (especially when you consider that it's free) but I was still working with a word processor and, while I can bend a word processor into something vaguely shaped like a layout program, it takes an awful lot of coaxing and prodding and screaming to get through a book-sized project.
So I figured it was time to find something that was actually made for what I was doing. The big ones, Quark and Adobe, are absurdly expensive. Also, Adobe has a long history of making software that irritates me, so I wouldn't be keen on that one even if it was affordable. Another small-press game designer recommended Serif's PagePlus, so I checked that one out. The price was reasonable, the reviews were good, and it looked from the tutorials to be pretty user-friendly. I bought it.
And I hate to sound like a commercial, but wow, it's perfect. I was making fresh progress on the Athebes layouts the same day. I was even able to pick up what I had done in OpenOffice and convert it because PagePlus opens and edits PDF files too. I'm actually enjoying myself again. Best investment I've made in a long time.
I also discovered AbiWord, which is a slimmed-down (and free) word processor that loads really fast. Nice for just writing when you've decided to do your heavy formatting work in another program.