O'Reilly are just the best
In January, I bought an ebook from them (“Search Patterns” because I have it in mind to improve the way searching is done on this site).
And then in a fit of enthusiasm and disorganisation, I bought the same book again last month, because I’d forgotten I’d already got it :-)
One email to O’Reilly customer services later, and they immediately refunded my card.
They really do have it right when it comes to selling ebooks: no DRM, all formats available, any number of downloads, discounts of future ebook versions of physical books you’ve already got.
Thanks, O’Reilly!