i'll start with a genre mostly neglected in this thread so far, one that was created in england, parallel to america's hip hop revolution (minus the funk influence): trip-hop.
- massive attack - england.
so revolutionary, they are usually referred to as the quintessential band of the genre. the original band of the artist tricky. featured in all sorts of movie soundtracks. you've heard them before, even if you don't realize it.
- portishead - england
- sneaker pimps - england (but only really the first album)
- lamb - england
- hooverphonic - belgium.
some from other genres:
- sigur ros - iceland.
- imogen heap - england (also only really the first album)
- the cure - england (disintegration, mostly)
- u2 - ireland
- radiohead - england
- paz lenchantin - argentina (but plays in american bands a perfect circle, zwan)
some already hotly debated (prophex v. the world):
- led zeppelin - england
- pink floyd - england
- clapton - england
- the beatles/wings - england
i'm really only listing the things i listen to on a regular basis. i've got a lot of stuff i don't play a whole lot from who knows where, everything from classical (which i assume we are excluding? i really like chopin and rachmaninoff), to marley, to soft cell and the boomtown rats, to bowie, to bjork and dido, to the clash...