Think it depends on what generation you grow up with as to what your best memories are. Personally I feel sorry for anyone who never got to see the genius of Keith Edwards. Winning the 4th Division Championship brought its own celebrations, the win against Arsenal that night at the Lane in the League cup when we were in the 4th division also.
Great memories of those days and then the Bassett era, when we beat all and everyone against all odds. Anyone who doesn't still remember that win at home against Forest the first season we were up is missing something! That double over the Pigs on their first season back (especially the one at the Sty). The glory of an away win at Anfield to be shortly followed (a couple of weeks later) by the absolute desolation of relegation pretty much sums up being a Blade.
Kids now will remember promotion to the Premiership and the subsequent season beating the Arse at the Lane, paddys save against Bolton, Jags winner against Boro they are all locking in the memory as brilliant times.
Each to their own because they are all equally significant.