For some reason, I haven't been keeping up with "The Simpsons" lately - probably because the DVDs are coming out faster, and I know that if I just wait patiently, I'll have everything. I don't plan to cut off my collection at Season 8, though, since the commentaries alone are enough to warrant my desire for the Scully years (it'll be interesting to hear Tim Long and Ian Maxtone-Graham try to cover their butts).
Season 8, if I'm not mistaken, was also the last year that John Swartzwelder worked in-house - once Mike Scully took the executive producer job, Swartzwelder's once-genius episodes became increasingly more horrible, and from what I understand, it's because he began writing elsewhere and sending his scripts into the studio to be reworked without his input. Perhaps this set's commentaries can shed some light on this (since Swartzwelder has never provided a commentary, there's a fair amount of mystery around him among the other commentators).