I'm very attracted to the Sony Reader.
I've read some articles about it, and it sounds pretty good, but I'm a little leery about buying an ereader that might not remain viable for very long. If I bought one, what would be the chance of it becoming unusable from format problems, etc.?
On a somewhat related note (because I'm trying to choose between all three of these devices), what would you choose if you had a choice between a DS Lite and a PSP?