I also didn't like when Muppet Babies replaced those great orchestral pieces composed by Robert J. Walsh (the same composer from the G1 Transformers and My Little Pony shows) with that flat, kiddy show-sounding '90s MIDI music composed by Robert Irving and Hank Saroyan in the last few seasons starting with "It's Only Pretendo". Though I did like how the title cards had different music each episode.
I felt the same way about the 80s Chipmunks cartoon: the first five seasons with Ruby-Spears had fitting music scored by Dean Elliott, but when they switched to Fred Wolf and later DiC, Chuck-Rucker Productions did the music - not that their other work is bad (hey, who doesn't remember all the various show-stopping numbers from Dexter's Lab?), it just didn't fit with the Chipmunks; like Drtooth said about Inspector Gadget, it just had that really flat 90s synth sound to it, which added to the cheapness of the show by that point (really, the DiC episodes have pretty minimalistic animation compared to the RS episodes).
John Williams- "Star Wars" and many 70's disaster movies: "Poseidon Adventure". "Earthquake", "Towering Inferno", etc.
Interesting trivia about John Williams: although he composed the now-familiar score for the first two HOME ALONE movies, he wasn't the original choice. Bruce Broughton was slated to score the movie, but at that time he was too busy scoring THE RESCUERS DOWN UNDER (which has some really good music), so they brought in John Williams, thinking he wouldn't do it, but he did.
On the subject of Bruce Broughton, there's a distinct sound to his scores, almost like he's able to really juggle the balance of cinematic and quirkiness (the Homeward Bound movies, for example).
That said, I find that the score is a key factor that can make or break a movie for me. Case in point: the original ICE AGE movie was a quirky movie, and David Newman can it a fitting, quirky score, and it was a good movie. But for the sequels, they brought in John Powell instead (since he seems to be Blue Sky's go-to composing for scoring), and he gave them a really overly cinematic score that didn't fit with the movies' atmosphere, which is one of the reasons why I don't really like the sequels. I mean, when I think of ICE AGE, I like to think of that guitar-rich ditty that was used as the theme for the first movie, not that big orchestrated "DUN-DUN DUN-DUN DUN-DUN-DUUUUUUUUUUN!"