Thank you for the ePub Tip!
Regarding a PDF reader for iPhone / iPod Touch / iPad
<shameless_plug>
gogoDocs is a Google Docs Reader (separate iPhone and iPad apps) that a friend of mine started in order to solve the problem of being able to take his Google Documents with him even when he doesn't have signal. <insert comment about AT&T in NYC here...> In gogoDocs, once you sign into your Google Docs account, you select which documents you would like to cache to your phone, and they are downloaded in the background. Likewise, when signal is restored and a document is found to be updated, it will download the update in the background.
While he was working on this, he noticed that the PDF renderer included in Cocoa Touch (I think it's from UIWebView, but I can't check right now) is fairly bad, so he rolled his own! In his renderer he has fixed the crashing and poor scrolling that plague most (including the Apple-provided) PDF renderers.
Two final features that I love are the Last Viewed Position bookmark and the Fast-Scrolling Bar. After returning to a document that you navigate away or close gogoDocs, a ribbon floats on the window showing the relative position of your Last Viewing Position. Clicking on this will return you to the page that you were last on. This disappears after a couple of seconds, but can be invoked by a button on the toolbar. Finally, there is a grabbable scrollbar similar to any desktop application when the content exceeds the viewable windows' size. (If you haven't noticed, iPhone 'scrollbars' only show relative position and size, but can't be dragged.)
I apologize for the shameless plug, but I really do love this app. It has become my favorite way to consume PDFs.
(Disclosure: I worked on it, but don't make any money from it's sale.)
</shameless_plug>