Ahh e-readers! I got the Nook Color and it's more expensive ($249) but I'm impressed with it. I've put some downloaded manga on it (you need to format it a bit, I used this guide): http://thegrownupsarelying.blogspot.com/2010/05/how-to-get-manga-on-your-e-reader.html

I'm hoping they'll offer e-manga for sale or something in the future. Formatting can be a bitch if the person scanned in double pages instead of single.