Originally Posted by Xenophon
As far as producing professional looking eBook, I've been having excellent luck starting from html and using html2lrf (part of kovidgoyal's libprs500). It does quite a nice job with minimal user intervention. The problem would be taking a book in one of the open formats that (say) Fictionwise sells and converting it into html without too much work. I've heard rumors that there's a convert-lit program that'll do that -- but I don't really know from my own experience.
Hope you find a good solution. And please let us know what you eventually work out!
libprs500 now includes lit2lrf which will convert non DRMed lit files automatically (It uses html2lrf as the backend)