I constantly keep hearing this "it has no backlight" argument.
If the PRS-505 came with backlighting by default, I wouldn't have bought it. Backlight causes eyestrain (like staring at a bloody light bulb) and I seriously don't see the need for it. Dead tree versions of books (the same ones you've been reading all your life) don't have it, and they don't need it. If it's too dark to read,
you turn on the light 
.
I think this stems from the fact that the Reader is an electronic device, and everyone wants all their usual electronic features on it. Like a calendar, internet access, audio playback etc. If more people realized that the Reader is just a very VERY good alternative for a p-book and tries not to be anything more (ok, it does--mp3 playback, who uses that?--but it
shouldn't), we would have more happy people.
It can store lots of books, and it can display them for comfortable reading. That's it. It's all it needs to do.
You can turn on the light if you need it.