I like this idea. I guess the first question is when do you think The Simpsons stopped being good? For me the last great season is 8. But there are some gems in season 9, more than any subsequent season (do to it including some holdover episodes from season 8). Off the top of my head I like the NYC one, ‘Realty Bites’ and ‘Cartridge Family’.

I think it’s important to have a Treehouse episode (you could mix and match the segments from different years). There should also be a Sideshow Bob episode. Not sure which I would pick. And it’s a good idea to get as much Phil Hartman as possible (his last appearance is in season 10).

As for closure, that’s a good point. I think the one where Maude Flanders dies would probably be a good inclusion (even if it’s a little depressing). Also ‘Behind the Laughter’ feels like a final season kind of episode. Not sure how far into the series you want to go, in terms of matching SD/HD episodes, but I vaguely remember there being some decent stuff in season 20 that could give a good sense of finality.

Last thing I’ll say is I would be cognizant of the different show runners. I find it’s pretty easy to feel a difference between them (I’m a big Oakley/Weinstein fan, myself. They did seasons 7 and 8). Seasons 9-12 were run by Mike Scully and everything 13 and on was Al Jean (with occasional Matt Selman input). Would the goal here be to pick one of those eras and stick with it, or try to get the best of everybody’s? That could be done too. Season 9 has three holdovers from the Oakley/Weinstein seasons AND two run by David Mirkin (who ran seasons 5 & 6).