Well.. it depends on what the OP meant by solo... live or recording?
Many, many, many guitarists are amazing on track, but are mind blowing on stage; like Angus Young for say. Sounds great on track, but bumps it up on stage. Not all guitarist are like that however... too many bands get so drunk while on stage they can't even play properly. :1orglaugh
Anyway, for the best guitar solo... A very tough question. Like I asked before, live or on disc? (not a "live disc" :1orglaugh)
For recording, "Let There Be Rock" by AC/DC is one of my top favorite solos. Even live, the way they used to extend it so much was great :thumbsup: