I'll go with my dear departed countryman on this one:
Rory Gallagher:
1: took visible, palpable joy in playing his ass off and seeing people dig it. No po-faced smugness from Rory. He was as into it as the Audience.
2: Could play any damned thing with strings on it. Really, really bloody well.
3: Helped kill showbands. Not sure how big these mohair-suited gangs of shiteehawks were outside of Ireland, but, if you're unfamiliar, trust me, this was a good thing.
4: Assimilated techniques from everywhere he saw them. He could, and did, throw together techniques as diverse as slide, harp-picking, taps, slaps etc. in the space of a song. Sometimes, in the space of a bar.
5: Loved that strat so much he even kept using it after it was stolen, and recovered lying in a shuck for three days. And it still sounded ungodly.