Too hard to pick. He'd definitely be in the top 3 with Jeff Beck and Roy Buchanan in my opinion. I can't decide who is #1.
Jeff Beck:
Can (and regularly does) carry a whole show or album with no singing need.
Much better solo than Page.
Best concert I've ever been too (and 2nd is not even close).
Roy Buchanan:
Probably the best overall in terms of ability of any guitar player.
Never lost the raw feeling in his music that younger less successful bands have before they become big time.
Taught Robby Robertson how to play guitar.
Jeff Beck bowed before his amazing ability.
Gave Charlie Daniels his first big break in music.
Jimmy Page:
Hands down the best song writer.
Widest variety of music (whereas Beck and Buchanan were almost exclusively solo artists).
Could rock harder than anyone ever.
Without Page 3 great musicians in Plant, Bonham and Jones probably never would have made it.
Highly creative (violin bow, mandolins, etc).
I don't really care who's #1. Let's be thankful we have great music like that made by Page, Buchanan, Beck, Clapton, Nugent, Hendrix, Vaughn and all the other greats.