First, thanks for doing six! You rock! (I guess literally even!

Also, I spent some time listening to QOTSA last night - as I'd hoped, a billion times better without the death metal singing.

Okay, on to your picks!
1. Army of Anyone - It Doesn't Seem to Matter
I'm not as familiar with Filter - another one of those bands on my to-do list based on what I've heard on the radio...but having just never gotten around to listening to full albums.
But I DO know and love STP (I know - big shock

I've heard this song before (via my interest in STP) and like it a lot. Great pick!
2. Fugazi - Waiting Room
I've not heard these guys before at all (although I have heard OF them), but this is another band I might like, as I used to quite enjoy punk. Might end up being a bit hardcore for me now, in my 'old age'

3. Butthole Surfers - Pepper
LOVE, LOVE, LOVE these guys, and this song (which of course I've heard many times). Not much to dislike about these guys. Except maybe their name.

My picks:
http://www.youtube.com/watch?v=hCYfNo__9zA&feature=related
http://www.youtube.com/watch?v=FGuJ3tvKgo8
http://www.youtube.com/watch?v=duDdTr2UiEQ