Saw the Angelic Upstarts at the Durham Punk festival last year - they were brilliant (as were the other bands). Had never liked them that much previously, as I've never been an 'Oi' fan, but had to revise my opinion somewhat.
It's often worth going to see a lot of these bands today. With 30 years or so playing behind many of them, they've mostly reached pretty good standards of performance, often with good new material. The Damned and UK Subs are great examples; Capt. Sensible's a fab guitarist, and Monty the keyboard chap is no slouch either. Gig atmosphere is more party-like too these days - I generally have a better time now and usually end up jumping around at the front despite being sober and 'mature'. Still younger than the bands though...
Andrew