How about the Asus T91MT tablet?
jswinden has an interesting comparison of his T91 versus his other e-readers here:
https://www.mobileread.com/forums/showthread.php?t=73724
I'm certainly very happy with both my netbook cheapie and my larger tablet PC. They both do every kind of reading that I need, from all book formats through to PDFs, online newspapers, forums, reference site and so on.
Cheers,
Chris