I like the 'Unleashed In The East' album. It's probably not really 'live', but it KICKS ASS !
'Screaming For Vengeance' is awesome too.
The thing about getting old is that you lose alot of energy and you get too comfortable, and that takes the heavy POWER away from your playing style

. Plus, in Rob Halfords case, you lose your vocal power and range, though he can still 'stab' at certain things every now and then.