This appears to be a hot topic. This entry from David Pogue:
Last week, Barnes & Noble’s Nook e-book reader took on Amazon’s Kindle, joining the Sony Reader and several smaller players. And that arena has only just begun to heat up; in the next few months, a raft of additional models will appear.
One of my readers is alarmed by a precedent being set:
“When the iPod introduced music lovers to the idea of copy protection, a years-long war ensued between consumers and the RIAA (and others). The primary issue was that if I purchased a song for my music player, it would only play on that player; I didn’t really own it, per se. Years later, we finally have digital music without copy protection.