Personally I thought the first 6 seasons of Scrubs were all ace, and I don't think they jumped the shark until season 7.
I know they had a lot of seasons/episodes, but it wasn't the same thing every season. The characters were actually living a life, they were getting promoted, they were ageing. In the first season they were interns, naive and looking to other characters for support. By the end they were the ones being looked up to, the ones giving support. These real life parallels and poignant moments were a big selling point for me.
Anyway, season 7 they ran out of ideas (and the writer's strike didn't help it either). Season 8 they decided to wrap it up, and I liked the ending a lot. It was fitting. It's just a shame, for me, they decided to make a 9th season. And it wasn't a spin-off, for me, because JD was in half the episodes, Turk was in pretty much all of them, and most characters made a few appearances. That really murdered the good memories I had of the ending.
However, I've since re-watched episodes, and you've got to give them credit for mixing comedy and drama so effectively. It was mostly comedy (often absurd, surrealist stuff), but in the face of a bleak setting. The dramatic moments brought Scrubs down to earth, and made it relatable. It was a great show. One which was stretched too far and too thin (it's the American way: you've got to either cancel a show before it has time to shine, or let it run for years after its already burnt out!) and one which was spoiled by a poor and unnecessary 9th season, but it was a great show nonetheless.
