best non guitar rock solo

I second the Ian Anderson vote. The "rock flute" solo (that does give me a grin every time I say it!) on Locomotive Breath is quite excellent.

And yes, you really need to throw Geddy Lee in there. Cliff Burton's "Anesthesia - Pulling Teeth" also comes to mind.

The Fender Rhodes solo in The Doors' "Riders On The Storm"
Keith Eerson's solo in the live version of "Tarkus" from "Welcome Back My Friends To The Show That never Ends.."

Organ from In-A-Gadda-Da-Vida / Iron Butterfly
Swapped a lot of spit to this one...

Paul Butterfield's harmonica solo on "Everything's Gonna Be Alright"
Steve Winwood's Hammond B3 Organ on Hendrix's "Voodo Child"
Violin solo at the end of The Who's "Baba O'Riley"
Opening piano solo on Elton John's "Funeral For A Friend"
Bobby Keyes' sax solo on the Rolling Stones' "Can't You Hear Me Knockin'"
Ginger Baker's drum solo on Blind Faith's "Do What You Like"

Mark Nauseef(drums, percussion, marimbas samples etc...) in his solo album Wun-Wun on CMP along with super voice performance of Jack Bruce.
Another superalbum is "Transmutation" by Praxis(one of the Bill Laswell's projects) I realy don't recall the name of the keybords master but he was faster than fusion!
And certainly everyone here should know the famous flute master Ian Anderson.
Also check out keyboards in Steely Dan not neccesarily solos and that is realy stunning even on the background!