@bdp24 - nope, didn't even know of Emerson 'til the first ELP record. Emerson was an amazing pianist and keyboard artist. There are video clips of him performing works of a classical nature. The whole "prog rock" thing got overdone, and lost traction, but I still listen to early ELP, I have a couple of The Nice on early UK pressings.
Leslie West- a whole other story. Lon-guy-land boy as I remember. I first saw him and Mountain (with the great Felix Pappalardi) open for Tull right before Aqualung was released. (I think Glenn Cornick was still playing bass). Leslie was a tone monster. No shredding, no impeccable fingering technique, but he could pull more soul out of a few notes than many more technically proficient guitarists. (The leads in Theme for an Imaginary Western come to mind).
FWIW, we went to hear Crimson a couple weeks ago. I wasn't a long time fan, only really cared about the first album, though I had passing familiarity with Red, Larks Tongue and a few other tracks from the Wetton era. (Greg Lake's voice on the first album was gorgeous, but got lost in the mix). This band put on one of the best shows I have ever attended- well produced, no sonic overload, tighter than hell- three drummers, everybody, from the woodwind player to the bassist, played dead on--
Very few "old" acts that are still around can even approach what they did in their heyday. These guys, from what I gather, are in better form than ever. Fripp, of course, was as inscrutable as ever- looking like a retired haberdasher or banker, sitting on a stool, conducting and occasionally playing these psychotic, psych fills on vintage Les Paul's that were run through synthesizers. Crazy good show if you can catch it.