My fave is Hotel California, I love it when Felder and Walsh rip into the solos. I was so disappointed in their Hell Freezes Over tour when they played it acoustic. They got it right their last tour, truly epic. Also, a little known dueling solos song is East/West by the Butterfield Blues Band, Mike Bloomfield and Elvin Bishop trading licks, a 13 minute marathon. Also, Robbie Robertson does some nice guitar work on Dylan's Blonde on Blonde album, particularly on Brand New Leopardskin Pillbox Hat.
I hate, Hate, HATE that song.
Makes my ears bleed, it does.