I just want to say that the FBReader UI is outstanding. You put it into portrait mode (you don't need Screen Rotation tweaks; it's a setting within FBReader) and you can tap the bottom half of the screen to go to the next page (or the top half for the previous page). You can even adjust within FBR how hard those taps need to be. There are a ton of useful settings.

For the primary font, I like using Sans at 20 in Bold. I find it very easy read, for me with some astigmatism and far-sightedness, while not too big.

I'm critical of some of the failings of the Tablet, but I'd really be surprised if the iTouch UI is better than FBReader's. (I wish other Tablet programs were so well-executed.)