I have the good fortune to be able to share with you not 1, but 2 articles on Android reading apps. One was written by Carly of GearDiary, and I wrote the other (as part of my review of the Archos 5). You should read them both. Carly and I came to different conclusions on some of the apps.
eBook Reading Options for Android (Gear Diary)
Reading on an Android Tablet, pt 1 (Nate's Ebook News)