since you have already mentioned some great ones, i'll expand the field a bit... first I must add the LIVE version of "Stairway to Heaven" (from Song Remains the Same). strange nobody mentioned "Freebird", Lynyrd Skynyrd. Though I don't listen to them much anymore, that solo is still pretty impressive. I really like Gary Moore's solo in "Still Got the Blues." add just about any Eric Clapton work ("Bell Bottom Blues," "Layla", "Bad Love", "Old Love", to name a few...) I also believe that is Eric playing the lead in the Beatles' "Something". I think Harrison pulls of a sweet lead in the guitar version of "Let it Be"...it's not difficult but has a lot of character! Has anyone heard Vinnie Moore's cover of "While My Guitar Gently Weeps"? Save for the canned rhythm tracks and slight overproduction, Vinnie's technique is pretty amazing. I'm sure I'll think of 10 others as soon as I stop writing so I'll add Hendrix "All along the Watchtower" (you guys already mention everything SRV ever did!)... Oh, and i like the original electric version of "Hotel California" better than the live one, though, both are nice. Pearl Jam's "Yellow Ledbetter" has some nice fretwork as well. and Carlos Santana has some tasty stuff throughout his career. Check out the Milagro! CD sometime...
Play your heart's out!