That's the only kind of ebooks (non-DRM) ones that I buy. Some publishers (like O'Reilly or Tor dot com) exclusively publish non-DRM books.

I politely ask authors or publishers to release non-DRM ebooks when I can. Apart from best-sellers (or time sensitive books), I believe most books are stuck in the long tail of obscurity and releasing them as non-DRM won't affect their sales.

This also means I don't visit pirate websites that claim to have ebooks. It takes two to tango. :-)