Another suggestion, if I may.
When you get around to implement OPDS support, please make downloading multithreaded. Every reader out there, except for Stanza is busy indefinitely while downloading. Imagine downloading a large book on a slow connection. Annoying to say the least.
Stanza downloads multiple books in the background. Even offers the choice to download all the books in a page, such as when you visit a series page and you decide to get them all.
Failing multiple concurrent downloads, then a queue that continues in the background while you surf the catalog or continue reading would be good.
And on the order of format support, I would like to see one other format. CBZ/CBR (comic books). I am half tempted to ask for PDF, but I really don't like the format on principle.