Of the ones mentioned, I gotta go with Comfortably Numb. As good as the two JP solos are they can't touch the Floyd solo.
There were a few important, and just plain good solos left out:
Ozzy Osbourne: Mr. Crowley. Randy Rhoads was a fucking genius, and this was probably his finest hour.
Iron Maiden: Stranger in an Strange Land: An underrated gem from the IM catelogue
Rush: La Villa Straingato: This is a solo that builds up perfectly before exploding with fury.
Metallica: Creeping Death: While the riffs are what really drive Metallica, this is a truly fine solo.
Savatage: Ghost in the Ruins: Criss Oliva was an underrated guitar player, and it's a shame he never really got the credit he did. This is a truly spectacular emotional, yet ethereal piece of work for him.