These topics...making me choose a favorite song is like making me choose a favorite child among a group where none of them disappoint...

I'm not going to choose current favorites because they haven't stood the test of time. So, my favorites are:

Tool: Third Eye
Alice in Chains: Would?
Dream Theater: Home
Smashing Pumpkins: Today
Soundgarden: Face Pollution
Opeth: Ghost of Perdition

If I had to pick one of these as a favorite...RIGHT NOW...as I'm typing this, I would say it's "Would?". This can chance with so much as mild breeze though.