I love The Simpsons , though I don't watch it as much as I used to I find time to watch the newer episodes here to there. I honestly don't understand all the hate for the newer seasons really. While I admit there's some of the newer episodes lack quality, but I still find alot of them entertaining and enjoyable. After 24 seasons you can't expect the quality to be as good as it used to be. The writers aren't gonna always have original ideas. I guess it's cause I grew up with seasons 13-18, I can appreciate the newer seasons a bit more. My dad introduced me to the show around 2001/2002 when we got cable cause I guess he figured we were old enough to watch it at the time. We'd watch the new episodes on Sunday and reruns on ABC every week day. As much as I liked the older episodes too, I was excited to watch the new ones every week. So I guess since those are the that made me really obsessed with The Simpsons as a kid, I really like them.
As for favorite episodes of the classic one, I would say "And Maggie Makes Three" or "Who Shot Mr. Burns?" are two of my favorites. "And Maggies Makes Three" has such a heartwarming ending and was one of the most touching episodes. "Who Shot Mr. Burns?" has such a funny twist to it that it makes it just really funny. I don't if this is called a "classic episode" but another favorite of mine is "Blame It On Lisa" . Apparently it got some controversy for the way it portray's Brazil, but it's one that really left me cracking up laughing when I was younger. It's from season 13 so I guess it more depends on what's your definition of "classic Simpsons" though I guess to most people it seasons 1-10. To me it's more season 1-15 but I guess people have their own opinions. I really like alot of the vacation themed episodes, one classic I like in particular is Thirty Minutes Over Tokyo. It's mainly cause of the reference to the infamous Pokemon episode , Electric Soldier Porygon, but i love the vacation episode because of the many ways Homer tends to screw things up in them.
As for newer favorites , I really liked the newest one Dark Knight Court. The whole parody of The Dark Knight Rises was rather funny imo, though it's far from my favorite of the modern seasons. I don't know if I have a favorite from the modern seasons, mainly cause I haven't seen alot of episodes from about season 19/20 and on though recently picked the show up with season 23 and there's a couple I really liked. "The Book Job" is definitely one of them cause it had a really great concept behind it and I thought Gaiman's appearance was great. I thought " A Totally Fun Thing That Bart Will Never Do Again." was good in my opinion, cause of the way it shows an emotional side of Bart and has a great ending to it. "A Tree Grows in Springfield" is one I watched recently and thought it was enjoyable. Reading the Wikipedia article on it, I learned critic say the episode was a throwback to early Simpsons and I definitely agree. The whole focus of the episode with the whole town believing the tree in their backyard with "Hope" splattered on it and late turns out to be fake reminds me of the episode "Lisa the Skeptic". (If anyone gets what I'm saying. I don;t think anyone does.Watch the episode and you''l probably understand. And it one of those episode that takes a small problem and blow it out of proportions and makes it humorous. Yeah I could go on forever about the show. And yeah I agree the older season has a special charm to them, I still can find the newer one enjoyable as stated.