Shoot, this question has changed a lot just in the ten years that I have been in the hobby. When I first started playing, anything stern put out was immediately trashed (maybe it hasn't changed all that much, although at least now there are more defenders).
IM came out and was hated, I love it. Now it gets its due.
WH20 was considered a hokey budget pin at best but now cracks the pinside top 20. Was and still is my favorite game.
Congo and Flintstones made me love Trudeau, Congo is finally getting a little credit thanks to Keith Elwin saying he liked it too. Maybe the Flinstones will head that way eventually as well.
But up to current feelings towards pins, I LOVE gottlieb system 1 and 3 games. Pretty much universally too, I love every one that I have played thus far and my Count-Down will never leave my collection.
Apollo 13 is an absolute blast to play and I don't care who thinks it sucks. So is Waterworld.
Anything Nordman has ever designed is fun to me including Wheel of Fortune, Indy 500, and Demolition Man that may not get too much love.
Another opinion that nobody seems to like: Stern Indy is great, but I don't like Williams Indy
Mostly popular games I dislike are Wizard of Oz, AC/DC, Black Knight +BK2K, GoT, Family Guy and World Cup Soccer