People seem excited about this iPod idea and i think they are missing a few little details.
Get this out in the open, i have an iPod and love it. So go for it if you want a nice new black edition. But this will not change the fact that you need to go out and get the new album (or any other albums you're missing) on cd.
First of all, as U2 fans you should want to get that album and boost U2 up the charts, but on a more practical note, the songs will be stuck on your iPod. you can't upload them to your iTunes, and it is another hassle and expense if you want to listen in your car. Also the albums will most likely be mp3 quality (at who knows what bit rate) unless apple decides to put lossless files of them on there, but they haven't announced one way or the other.
I say go get the U2 albums on cd, download them to iTunes and iPod and get to have the CD for your car and friends stereo, etc.. and of course the liner notes and booklet and everything. Along with that giving U2 actual album sales that will reflect on the Billboard charts.