My main band, The Manic Street Preachers (who incidently are welsh)
One of the best bands to come out of Britain in the last 15 years.

Mew
Stereophonics (welsh too actually!)
Queen
Suede
The Raveonettes
The Hives
Blink 182
Blur
Oasis

And I like a lot of seperate songs by tons of different bands

Not a solo singer fan but I do like
Elvis (naturally)
Robbie Williams
James Blunt
Elton John

and some songs by various others