It’s about personal favourites, not “best/most significant” etc.
The only rule is that you can only choose a band once, so no, like, 20 AC/DC or Zep songs.
Definition of “solo” is also up for personal interpretation.
All that matters is that, every time you hear it, it moves you.
Here’s mine:
Don’t Worry Baby/Los Lobos/David Hidalgo & Cesar Rojas
Voodoo Child/Jimi Hendrix
Take It So Hard/Keith Richards & the X-Pensive Winos/Waddy Wachtel
My Morning Song/The Black Crowes/Rich Robinson/Marc Ford
Sympathy for the Devil/Rolling Stones/Keith Richards
Rikki Don’t Lose That Number/Steely Dan/Jeff “Skunk” Baxter
Cinnamon Girl/Neil Young & Crazy Horse/Neil Young
Panama/Van Halen/Edward Van Halen
Jessica/The Allman Bros./Richard Betts
Superstition/Stevie Ray Vaughn
Pretty Woman/Roy Orbison/Bruce Springsteen & James Burton
China Grove/The Doobie Brothers/Jeff “Skunk” Baxter
Aqualung/Jethro Tull /Martin Barrere
Absolutely Sweet Marie/Jason & the Scorchers/Warner Hodges Jr.
Desolation Row/My Chemical Romance/Ray Toro & Frank Iero
The Rover/Heartbreaker/Led Zeppelin/James Page (sorry, tie on this one)
The Bends/Radiohead/Jonny Greenwood (I know, “solo” in the broadest interpretation, but still…)
Murder Incorporated (Live)/Bruce Springsteen & the E Street Band/B. Springsteen & S. Van Zant & N. Lofgren
Old Folks’ Boogie (Live)/Little Feet/Lowell George
You Shook Me All Night Long/AC/DC/Angus Young