Best concert is very difficult as there are far too many but some that stand out for me ( going back to the late 70's and moving forward to the 90's )
Rush and Max Webster at Liverpool Empire
Styx front row Liverpool Empire on the Grand Illusion tour
Blue Oyster Cult Liverpool Empire on the Spectres tour
Sammy Hagar & Riot Liverpool Empire
Kiss Stafford Bingley Hall. The 1st tour with Eric Carr when he wore make up
Motley Crue & Cheap Trick Manchester Apollo
Alice Cooper Manchester Apollo on the Nightmare Returns tour
White Lion & Tyketto Manchester International
Mr Big Manchester Apollo
Bullet Boys Manchester International
White Sister Manchester International ( I think they were support to Bullet Boys but I can't remember although they were definitely support to someone )
Aerosmith Birmingham NEC
Legs Diamond London Marquee
Mark Free The Gods Manchester Ritz
Dream Theater & Spocks Beard Manchester Acedemy

Worst gig was Iron Maiden on the Somewhere In Time Tour. They were so boring and had the crappiest sound for a major act. I got rid of all my albums afterwoods and have never bothered with Maiden since.