This album so far feels like it combines some good areas from each of the bands pasts.
While some are trying to define the sound; what album it sounds like, what we can expect etc, so far I hear a lot of albums in this.
U2's progression has often come from exploring new sonic territory. With the number of songs in their back catalogue, that is becoming more and more difficult, which is probably why many were so disappointed with Bomb.
I think that the source of the 'new' ground in this album is fusing the great points of many other albums.
Adam's bass reminds me of The Unforgettable Fire. He was creative, played counter-melodies, and really was brought to the forefront of the sound. Indian Summer Sky and Boomerang (I and II) are great examples. There is also a lot of War in his style.
Larry's drums, as mentioned by LemonMelon above remind us a lot of Pop. They are the least clear in these clips, but he seems to really be pounding the skins in some songs, and isn't afraid to try and explore new beats and rythms.
Edge's guitar sounds to me like a fusion of a few sounds. The heavier songs have Achtung Baby all over them. The heavy distortion, the fast pace, they sound very well produced. The quiter songs (clip 1 and 5) have a bit of Unforgettable Fire in them, especially A Sort of Homecoming live. There is also some HTDAAB on the rockier songs.
Bono has returned to form for the first time since the early 90's. His voice has been strong of late, but not as clear or powerful as it was. His voice sounds pure and confident, and I am hearing Rattle & Hum, and also Achtung Baby.
So, if this is any indication, I think the 3 albums for me that have influenced the sound of this record are The unforgettable fire, Achtung Baby, and Pop.
We can hopefully expect something with the vision, purity, honesty and creativity of UF, the experimentation and boldness of AB, and the fun, funk and sonic expansivness of Pop.