Absolutely any made by LucasArts in their heyday. The Broken Sword series. Beneath a Steel Sky. More recently, Telltale's fare fits the niche, though they aren't pure Point and Click. The Longest Journey has been extensively mentioned for good smurfing reason. I think The Last Express might count too? Another one that isn't Point and Click per se, but it's the exact same type of adventure game and though it doesn't entirely succeed in everything it tries to do, it's hugely imaginative and very much worth playing.

I don't know if you can get better than vintage LucasArts and Broken Sword though.

e; the Discworld games were also good, especially the first, which was excellent. I enjoyed Blazing Dragons a good deal although I can't really say it was particularly good as such.