I know that I don't know much about guitars...but in my struggle towards speed, I have learned this:

Speed is not so great.

I noticed that these people you have all talked about are about as fast as one can get. If you play too fast, you don't hear anything. It becomes a huge blur and doesn't sound very nice at all. Which is why I support Slash and Hammett as one of the top guitarists of all that still use some speed. It's a challenge to be able to play fast and still put in that emotion that I'm sure you all feel when a good solo is heard. That little sound clip of MacAlpine kicked my ass. And at points it sounded good. But somewhere in the middle it started to sound like a computer going AWOL. You just hear little bleeps all mixed together. That is when you are TOO fast! These guitarists you all mention ARE fast...I cannot deny that in the slightest. But speed can be overrated in the guitar world.