Check out the Aluratek Libre and Ectaco jetBook/jetBook Lite (all have 5" screens). All of them support DRM Epub, and are close to $100 (Libre is $99 at Borders, jetBook Lite is $99 at Newegg with a free case). Both use a reflective TFT screen, so it is faster than E-Ink but has a little worse contrast than E-Ink Pearl (I'm not sure about older E-Ink). A lot of people, including myself, like it better than E-Ink.
Not everyone likes these readers but you should check them out. And, as an added benefit, they don't have a clock, so library books don't expire on them (if you don't hook it back up to ADE, IIRC), so you can take all the time you need reading the books.
