Noticeable omissions:

1.) Tush - Billy F. Gibbons
2.) Boys Are Back In Town - Scott Gorham / Brian Robertson (Thin Lizzy)
3.) Surfin' With The Alien - Joe Satriani (*any guitar solo list devoid of Joe Satriani is, IMHO, not a definitive list. Joe rules.)
4.) One Way Out - Duane Allman / Dickey Betts
5.) Walk On Hot Coals - Rory Gallagher (*off of the Irish Tour album)
6.) Sultans of Swing - Mark Knopfler (*how in the hell could this not make the Top 20?)
7.) About 3/4 of Johnny Winter's studio and live catalog.
8.) You Got Lucky - Mike Campbell (he of Heartbreaker fame)
9.) Drive My Car - George Harrison (*seems like a crime to me that neither George or John are ever included in a greatest guitar solo list, esp. when considering that they've written some of the greatest songs of all time.)
10.) Just about all of Jeff Beck's solo catalog.
11.) Most, if not all of Frank Zappa's catalog.

There's my short list.