Categorizing DSO as avant-garde feels really weird. It's basically just normal pieces assembled in an abnormal way. Then again, I don't know what the hell avant-garde really is, I guess.
Also, I dare say Muse leans a lot more toward alternative rock than prog, but that's just me.
I've been listening to a lot of new wave/post punk like Elvis Costello, Siouxsie and the Banshees, etc. lately. I mean, I always do that, but it's kind of at the front of the list right now.