I did say "a bit proggy" - and if Rick Wakeman agrees with me, then surely that says something!
It's not just Rick -the media at large seem to have lumped them in with Prog;
Progressive rock: Encyclopedia of Modern Music - Times Online
Prog, as in the music of King Crimson, Gentle Giant et al. doesn't really exist any more as far as I can tell - what is called Prog now is just some standard rock music that sounds a bit proggy and has stupidly long instrumentals based on a handful of chords - like Krautrock, which is not a form of Prog, but something entirely different that evolved around the same time, inspired by guess who... yup. Pink Floyd mainly! Interestingly, PInk Floyd often come up for debate as to whether they are a "proper" Prog band or not, so beingn *inspired* by them does not mean you play Prog!
On Metallica's early albums, the band used the same riff development technique used by King Crimson on "In The Court of the Crimson King", specifically in "21st Century Schizoid Man", yet Metallica do not sound like King Crimson. Does this make Metallica a Prog band?
What about other modern "Prog" bands - which, if any, are actually progressive?
More importantly, how?
Which simply have a sound, and which actually do interesting, developmental (ie progressive) things with the music that makes it new music rather than music that sounds new(ish)?
I'd say very few - hence Muse have as much right as any band around now to be called Prog. Especially with the much-touted Prog epic "Knights of Cydonia" on their last album, and the 3-part "Exogenesis Symphony" which will be on the new album "The Resistance".