The Best of 1990-2000 is one of the worst compilations ever.
1) "Electrical Storm" isn't fit to eat the shit of some of the songs it pushed off this album. Not only that, but it has absolutely nothing to do with 1990-2000. Likewise with "The Hands That Built America" (which I forgot was on there until I read tim's reply), which is one of the worst songs they've ever done, ever. I'd rather listen to "Red Light" while someone's smashing my brains out with a brick. I'd rather listen to "A Man and a Woman"--okay, maybe that's taking it a bit far, but it's still not a good song.
2) While "Beautiful Day" and "Stuck In A Moment..." qualify strictly speaking (just barely), they belong on the next compilation. It's obviously supposed to be a nineties compilation. "Beautiful Day" signaled a second drastic change in direction for the band. It's such an obvious dividing point, I'm still totally dumbfounded they put it on the same disc as "Even Better Than the Real Thing" and "Discotheque." The freaking Grammys didn't even consider ATYCLB a proper 20th century release.
2) No "Lemon" or "The Fly" (imports can blow me). "If God Will Send His Angels" or "Please" also belong there, but I can understand their omissions since they weren't huge songs for the band. But for God's sake, "The Fly" broke them into the nineties (the first drastic change in direction) and, also for God's sake, they toured with a 40-ft. lemon. I remember reading an interview where one of the band members said they wanted "I'm Not Your Baby" on there too, which would've been a hell of a lot more interesting than either of the two new songs.
3) The track order sucks.
4) The new mixes suck. I know what you're thinking. "Surely, new stuff is better than no new stuff." No, it's not. I'm a lesser person for having heard them. They eat at bits of my soul. I sometimes wake up in a cold sweat screaming, "DON'T HURT THE BOOM-CHAS, YOU JUST LEAVE THEM ALONE." I have been unable to sustain an erection since hearing the castrated rhythm section of "Staring at the Sun (Total Shit Mix)."
Brownie points for "Hold Me, Thrill Me, Fuck This Ginormous Title," "Miss Sarajevo," "Until the End of the World," "Gone," "Stay," and "The First Time," though. But in all, U2 should've spent more time anthologizing the nineties and less time apologizing for it. I could write pages on the suckitude of the B-sides disc, but I'll spare you.
As for the The Best of 1980-1990:
1) It could've done without the stupid edits.
2) Drop a Rattle and Hum track. I'd dump "When Love Comes To Town" (even though they toured with B.B. King, so it's an important piece of their history in that regard). And move them around in the tracklisting instead of just smooshing them together at the end.
3) How about some fucking October? The hidden track doesn't count. In addition to "Gloria" (gee, think they played that one live a couple of times), "11 O'Clock Tick Tock" is a huge omission. "Out of Control" or "The Electric Co." would've been cool too, but they aren't as important as the other two. In general, there was too much emphasis on their later material. Yes, you sounded like a girl on the early stuff, Bono, but we liked it all the same.
Other than that, though, it's great. The tracklisting is brilliant, particularly the whole arc from "Bad" to "Sweetest Thing." Major, major brownie points for putting "The Unforgettable Fire" on there. The B-sides disc was also extraordinarily good (even if it also had stupid edits). Like, better-than-some-bands'-actual-albums-and-I'm-not-just-saying-that-because-I'm-a-fanboy good. The tracklisting there was also pretty good (even if all the R&H tracks got smooshed together again).
Both had very nice artwork.
I didn't notice that...
Electrical Storm (or any other lead single for this Best Of)
) and they should have put another 3 songs, like Gloria, Running To Stand Still and One Tree Hill or In God´s Country. Also I´d cut out When Love Comes To Town. Running Time is just 65 minutes long 
