I've been using Palatino 3 mostly. I like to keep the font size comparable to what the print book would have, so I keep it on 3 for i.e., young adult books and sometimes switch it to 2 for others where the text would be smaller.
Edit: I find myself using Palatino 2 more now. Less white space on the page makes the color blotches on my unit slightly less distracting.
Last edited by 7hir7een; 10-14-2012 at 02:19 PM.
Reason: updated info