After dodgy beginnings in the 80s as Freur, Underworld became the electronic dance band of the 90s & 00s, not least in Japan where I saw them a couple of times and interviewed them during a British Council project. Still great. Ultramarine also began life in the 80s under a different name (A Primary Industry) and released a few great albums of folktronica (before the term was coined) in the 90s, the standout being Every Man and Woman is a Star, before fizzling out in the 00s. One of the best gigs I ever saw was them and Bark Psychosis above a pub in New Cross. To complete the electronica trio, I'd have to include UNKLE. Their Never, Never, Land is as good as Massive Attack and they 'do' guest vocalists a lot better than Chemical Brothers.
Going back a bit, Urban Sax have to be in there, though they're first and foremost a spectacle not a recording group. I have happy memories of numerous 'concerts', playing football with them in Nancy (there were enough of them to form two 11-a-side teams) and crashing out on their manager Gilles' sofa in Montmartre. They're still going. Belgian band Univers Zero are definitely Top 10 who, along with French band Art Zoyd, spearheaded a kind of avant chamber rock as part of the Rock In Opposition movement... but I haven't kept up with them since the mid-80s.
U2? Well, they'd have to be in there wouldn't they? Of course, the Eno-produced stuff got me more interested, especially Achtung Baby and Zooropa. As stadium rock bands go, U2 are better than most. It was of course at Wembley's Live Aid that they made their mark, whereas Ultravox's performance that day was the beginning of the end for them. Still, I have a soft spot for them, both John Foxx and Midge Ure incarnations. I gather they've reformed.
The Undertones were all that was great about new wave: no-nonsense urgent pop by pale, thin young men with bad haircuts andno fashion sense (Feargal's parka is an abiding memory). UV Pop was John White from Sheffield who made great new wave(ish) / experimental pop and remain little-known favourites, compared with all the other Sheffield acts of that era; their Serious single is a minor classic. And finally, mention must be made of The United States of America for their one weird 1968 psychedelic-experimental album.
I should also mention Rachel Unthank, The Underneath (one of Kark Blake's many bands), United Future Organization, Vladimir Ussachevsky, (Ashra's) Lutz Ulbrich, The Unknown Cases, Uilab and, er, UB40 and Uriah Heep?