Two years ago, my life was changed. I saw an all day show with:

Breaking Benjamin
Three Days Grace
Staind

(and a few other bands)

and what really blew me away was when (much like when I saw 3DG and BB together with Nickelback) Ben Burley came out and sang Are You Ready with Three Days Grace. This was also performed vice versa with Adam coming out on stage with BB to sing Dance with the Devil. IT WAS AMAZING. Seriously, beyond one of my wildest dreams coming true that day, I think that their voices worked so incredibly well together, and I have yet to find an actual *studio* recording of this... I think it should it be done and released. Much like when Seether and Amy Lee teamed up (although I don't think a love song would come from BB and 3DG), two powerful voices like that one record/single... that's... damn hot.