U2 For Sale on the iTunes Store
Likely due to their concerts in Montreal this weekend, much of U2's catalogue is on sale at iTunes. $7.99 albums, $0.69 songs and $0.99 videos. Even if you've got most of their library in various forms, there's the remastered versions of The Joshua Tree, The Unforgettable Fire , Under a Blood Red Sky, October or War that will likely sound better than the versions you have now.
I'd hold off on buying a copy of Achtung Baby or Zooropa since there's remastered/repackaged versions of those albums coming out this year.