Over at Anne R Allen's blog about writing, she has a post on rejection. Basically rejections are often a mater of timing. ie. the publisher already has too many of your sort of book, or is broke but not going to tell you that, of course, or has had a change of editors and now wants something completely different to what they were doing before. It's bad luck for you, especially after all the effort you've put into the book. Allen's point is that rejections are very rarely personal. Sometimes they are, but only if you've behaved very badly first.
Have a look and a laugh. Especially her comment about framing the rejections. How much wall space does she think we've got?
Have a look.