Just wanted to add that Stanza is drag and drop also.... When you have the iPad attached just click on the "apps" tab. Scroll down and there will be a the apps you have installed that support the drag and drop feature. Comiczeal and Stanza if installed will be listed. Select the one you want to add items to, and then drag the files into the box to the right of the list of apps.... that's it
As I said all non-DRM ePubs, just use iBooks. If you have any PDF's use Goodreader, which also supports the drag and drop. Goodreader is $.99 in the app store.... But if you wait until the iBooks update later this month, it will also read PDF books.....