@ drop dead ed
I got the Black Keys' album, and the surprise was the fact that the CD is heat sensitive. It is completely black when you get it but once you take it out of your CD player it is vanilla white with black text. It slowly fades back to black over time, then you can mess with the coloring just by touching it (fingerprints and such). I had no idea there was going to be a surprise in the first place, and I personally found this SO COOL.
The songs are good too. Simple, dirty stuff.
I'm looking forward to Coldplay's album. They're not that great, but I'm very excited to see where they're going - they are one of the few way-mainstream bands I know of actively pursuing non-mainstream ideas (weird time signatures, unexpected instruments, unconventional arrangements, all done in a completely sincere and organic way).