I first saw him in Liverpool in the early '70's as a support artist to Free (I think). I was blown away by the stage performance and from then on used to travel the length and breadth of the country to see him.
A small group of about eight of us managed to get tickets to a Liverpool University New Year Bash (Top Rank of all places) in Liverpool, and it was so poorly attended that there was only about 20 people there in total. Osibisa were the support, but it was a gig that allowed me to get so close I could almost touch the great man. He must have thought I was some kind of nut just stood there (jaw dropped) for the whole gig.
Admittedly Rory Gallagher live performances rarely transfer to vinyl, though the BBC Sessions CD's are quite good, and the Live in Europe has a good Laundromat version. Probably best for Blues afficionados is the Taste Live at the Isle of Wight, where he demonstrates his unique blend of the Blues. The solo's go on a bit, but this was a performance that literally saved the whole Isle of Wight Festival. It's no wonder Hendrix gave his skill the nod.
Here was a man that Keith Richards couldn't face; a man adored by fellow players; a man sorely missed.
There is a tribute band out there called Sinner Boy. Worth a look.