Aside from a number of one-time Super Bowl Commercials, it's been a long time since I saw a commercial that I really liked and wouldn't mind seeing again and again.
If I had to guess when I stopped enjoying commercials, I'd say mid-90's. Yeah, pretty much when parents started their little take over of Kid's Shows. I think that when the shows went downhill, commercials did too.
Until I can compile a nice list, here's a Drug PSA I just LOVED watching. I mean, it's absolutely brilliant!
http://www.youtube.com/watch?v=NTYXZ0qZZEASeriously, it was the best.