That's the topic of
an editorial I posted to TeleRead today.
As was stated elsewhere in these forums, Fictionwise has said it is not planning to come out with an iPad-resolution version of its eReader, leaving iPad users with substantial eReader format libraries out in the cold. It seems pretty clear B&N is pulling the same stunt Amazon pulled on Mobipocket when it was going to release an iPhone Mobipocket reader app (and is probably pulling on Stanza, now, too).
I guess it's time to look for the next easily-crackable format to buy e-books in.