It seems that The Book Designer web site runs a monthly competition for the best designs for an ebook cover (or e-book cover, as the site chooses to spell it). If you follow this link you will arrive at the page recording the winners for November 2012.
The results make interesting viewing, and almost without exception they confirm my belief that most ebook covers -- or at least those designed by 'professionals' -- are grossly overburdened by information and are generally less than wonderful in meeting what ought to be the design brief.
Anyone with any wit surely knows that ebook covers are going to be viewed mainly in thumbnail form. And that is the key format, because that's the one which determines whether a potential reader cum buyer is going to bother to look at the sales page at all.
But... If you got to Amazon.com, books, fiction, last 30 days, and list by publication date, you get a reasonable set of examples of what is being offered by way of 'design' for the covers of today's new ebook novels. And most of these designs, quite frankly, are bloody useless. Here are three chosen pretty much at random from the first page:
In each case the title and/or author's name is largely illegible, at least to my elderly eyes, and the illustration gives very little clue as to the genre. The one on the left might be a Regency romance, but I wouldn't bet money on it.
My own view (doubtless hopelessly biased) is that any reasonably computer-savvy author can easily design her own cover, and in most cases it will turn out to be at least as good as something commissioned from a professional. Why? Because the professionals (on the evidence of Amazon) seem to be still thinking in terms of mass-market paperback.
All a good ebook cover needs is a highly legible title, highly legible author name, and perhaps an image of some kind to reinforce the perception of genre which is created (ideally) by the title.
Here's a good example which author Camille Laguire designed for her own book:
Go take a look.