Reunions: Hooray or Go Back To The Grave?

Everyone's reuniting: P.I.L., Wire, Dinosaur Jr., Pavement, My Bloody Valentine, the Specials, Sunny Day Real Estate... even lesser-knowns are rumored to reunite like mid 90's post hardcore/emo band Cap'n Jazz... What next? The Smiths?

Your thoughts???

Should bands/artists just move on and not try and bring back those 'Glory Days', or is it a great opportunity for those who didn't get a chance the first time around and/or a happy revisit to those who did?