Slightly off-topic, but what other killer e-book/e-magazine (e-periodical?) content is out there for plugging into Stanza like this? I've downloaded PDF versio

Slightly off-topic, but what other killer e-book/e-magazine (e-periodical?) content is out there for plugging into Stanza like this? I've downloaded PDF versions of my bookshelf of tech/development books and piled them into GoodReader, and that became my iPad's killer app #1. This Stanza feed thing looks like #2, if there's more stuff out there to plug into it.