This post is me speaking as a bookseller rather than a blogger. If you're designing a book cover, make sure the author's name and the title are 1) easy to read and 2) easy to distinguish.
I was doing up my 'Upcoming SFF' post for May books and came across this title.
I remember this author's books at the store. I remember thinking, for the longest time, that the title of the book was 'Nors', because that's what you could see from a distance. Obviously, upon closer examination the title is The Whispering Muse, which means Nors is the author's name. Only it's not. The author's name is Sjon. Now, the accent on the 'o' should probably have tipped me off that I was reading the letters upside down, but some languages accent below the letters, so I'm not entirely crazy for thinking my reading was correct.
The problem with this cover is that it's confusing. It looks fabulous as an art piece, but as an informational statement about the book, it's fulfilling its purpose.
Again, speaking as a bookseller, you want people to quickly, easily be able to pick out your title and name from the cover.
Another thing to look out for is using a name in your title. I can't tell you how often we found Jaqueline Winspear's Maisie Dobbs shelved under 'Dobbs'. It's a VERY easy mistake to make when you've got a lot of work to do and not quite enough time.
Make your titles clear and put your name in a readable font.
This is equally important for ebooks, though shelving becomes less of a concern. With small thumbnails to pick books from, making the fonts easy to read, and the title and author's name separated out clearly, is necessary.
End rant. :)