The short version:
Afrocelts—Sound Magic: 6/10
Death Cab for Cutie—Transatlanticism: 8/10
I tried out the first Afrocelts (or Afro Celt Sound System, depending on which name they're using at the moment) album, Sound Magic. It's pretty much like all of their other albums; that was the last one that I didn't already own. That's not a terrible thing, but most of the songs aren't memorable enough to warrant buying too many CDs, I think. That said, they make some cool world-ish music, mixing Celtic and African themes and electronica—the electronica influences here are pretty subtle, becoming more prevalent in their later albums. It's good background music, but it doesn't really maintain enough excitement to keep me interested for a long time. Anyway, it gets a "not bad" rating of 6 from me. Listen to Inion / Daughter, Sure-As-Not / Sure-As-Knot (Jungle Segue), and Dark Moon, High Tide / Farewell to Eireann.
Then I moved on to Death Cab for Cutie's album Transatlanticism... and I like it a lot. I think that most anyone who liked the recent CD by The Postal Service will enjoy it... it's got the same male vocalist, the same great writing, and the same quirkiness. In fact, I could probably mistake the Postal Service CD Give Up for a remix album of a Death Cab for Cutie CD. Death Cab is more rock-oriented and isn't nearly as absurdly electronic, but the style is still very much the same. I'll definitely be checking out more Death Cab in the future. For great examples, take a listen to The New Year (:30 sample), Title and Registration (full download), and Tiny Vessels (:30 sample). All of those sound great and have really interesting lyrics.
I think that next I'll try out Bubba Sparxxx—The Charm and Shea Seger—The May Street Project.