British music after the 1990's is actually pretty good.Im not a big fan of the 1990's,but most Post-1990 bands that i like are British.Oasis for example,are the best thing that happened to music during the 1990's.I dont give a rats ass about how stuckup they are,or how they might think that they're bigger than the Beatles..but Oasis are class,Period.
But other than Oasis there are a lot of other great post-1990 great British artists.Blur,The Verve,Amy Winehouse,Kasabian,The Prodigy,Massive Attack etc.
Good Music is Good Music regardless of wether its American or British,but its wrong to say that British music after the 1990's has sucked.