the original kindle didn't, but all of the sony readers do, as well as the kindle 2 and kindle dx. dunno about the others.
actually, the sony reader reads most of the drm-free formats, like epub, txt, rtf, word docs, etc.
charlie's angel, you're the kind of person who sells your games after you've played them once, aren't you? i save everything i've read, just in case i want to read them again. that way i don't have to buy it again if i want to go through a big series again. besides, how much do you get for a mass-market paperback? a dollar? that book's worth more to me than that =)
tinus, sony's readers allow for text scaling, but you have to do it in the program that comes with it, i think =( oh well.
most ereaders, due to the refresh rate, suck with textbooks unless you just want to read them like a book. hard to go back and view other stuff.