I think Tony Banks had the best solos in the context of what the rest of the band was playing, particularly when Steve Hackett was providing his incredible atmosphere. Damn, those two sounded so good together, it's a shame they only worked together for a short period of time. For example, the keyboard part in Cinema Show by itself isn't particularly great or impressive, but what made it sound so good was the bass, the drums, and the guitar. I do think Genesis had the best keyboard parts, up until the point Hackett left, then it unfortunately changed for the worse.
Wakeman and Emerson were more flashy, and technically more proficient. On their own, I think they had better keyboard solos. Wakeman shines in Awaken, Close to the Edge, and Siberian Khatru. Emerson destroys in Tarkus, Karn Evil 9, and Toccata, but I love his piano work in Take a Pebble best for some reason.