I think this round comes down to personal preference for a lot of people. That's what I expect to see in these later rounds.
On one hand, you have the kings of arena rock in Queen. Their two shittiest songs - We Will Rock You and We Are the Champions - are arena rock anthems that will live forever as long as Disney is churning out films like The Mighty Ducks and Air Bud. I've said it before - Queen is the greatest band in rock music history. Nobody has done what they have done. They would take genre's of music that other bands built an entire career around, do ONE song from that genre, and then move on. There was so much variety, and so much talent in this foursome. Freddie Mercury is also, hands down, the greatest rock frontman of all time.
Justinsayne was also spot on about Sabbath. I personally preferred Ozzy's solo work to Sabbath, but as the tournament cliche goes, "you can't deny their influence." When Justin said:
they were one of, if not the first band to ever play darker songs, they took a huge gamble and thankfully it worked, cause with out them we wouldn't have metal, a genre an music that is still going strong today
...he was more right than I can say. If Sabbath failed, the landscape of music might be totally different than it is today. I am nothing short of uber impressed with the band's work.
Here's one difference. Queen has basically fallen off since the death of Freddie Mercury. The original lineup was SO important to the dynamic of this band. I saw them play Nassau Collesium with Paul Rodgers from Bad Company, and it was such a let down. With Sabbath, they did very well with Ronnie James Dio as their lead singer. Some even feel Sabbath was better with Dio as their frontman. So few bands have been so solid as a unit that interchanging parts was never really an option - The Beatles one of the others.
I voted Queen, of course, as I will against everyone they meet in this tournament. I truly feel they are the greatest rock band in history and I hope they win the entire tournament. But you gotta respect Sabbath.