Ladies and gentlemen, I present to you Paper & Sage, which I consider to be the best e-book cover designing service I've encountered. I liked it so much that I put down my own money to get a cover created. I can't reveal the cover just quite yet (it's for a secret project), but you can take my word that the final product was up to snuff. The cover wouldn't look out of place next to anything you'd find in a bookstore.
When I went hunting for e-book cover designers, I found most sites fall into one of two categories. Either they offered inexpensive pre-made covers that looked just as cheap, or they offered a full service designer way out of my regular-person-living-in-the-real-world budget.
Paper & Sage is a little different. You choose from pre-made covers at a reasonable price, then hand the reins over to a designer who will make tweaks according to your specifications (colors, verbiage, fonts). If you need several big changes, Paper & Sage offers a custom package for a higher price.
This arrangement means you can get the benefits of a one-on-one designer experience at the cost of a pre-made cover service. Even better, once a cover is sold, it won't be offered again.
Paper & Sage didn't prod me to write this review. I did it on my own because the people doing things right deserve to be recognized. And Paper & Sage is definitely worth your dollars.