These are what I'd recommend to anyone, just going down his filmography. Almost all of the list is what everyone recommends though, but that just goes to show that I don't think they are wrong:
-Drunken Master
-Project A
-Wheels on Meals
-Police Story
-Armour of God
-Police Story 2
-Dragons Forever
-Armour of God 2/Operation Condor
-Drunken Master 2/Legend of Drunken Master
-Rumble in the Bronx
-Police Story 4/Supercop
-Mr. Nice Guy
-Who Am I?
-New Police Story
I know Snake in Eagle's Shadow is also supposed to be great but I've never seen it.
Top films for me are Police Story, Dragons Forever, Drunken Master 2, and then Rumble in the Bronx up to Who Am I?
EDIT: Police Story is one of the best action films of all time. Dragons Forever has my favorite of his fights with Benny the Jet and also has a cool/cheesy villain (I wish I could get to my gif of his slide down the stair case railing but imgur isn't loading it for me right now). Drunken Master 2 is legendary. Rumble was one of my first Jackie Chan films and will always be special because of that. It also has some great stunts for it being his older 90's work, has a story that I enjoyed back then, and is so cheesy at times that it's good. Supercop is maybe the weakest of that era but I like the aquarium scenes a lot still. I outlined a lot of great stuff about Who Am I? below. And then Mr Nice Guy I only caught a few years ago after having seen all of the others from that era multiple times, so it is the freshest for me (and Miki was insanely cute). I also liked the character he was playing in that more than some of the others.
I can't remember if it was good, but we had Jackie Chan's Who Am I recorded on VHS and watched it a lot as a kid.
Who Am I? is great. It's got some really cool settings and scenery (Rotterdam, the rally race through South Africa), some great stunts (the
slide down the Willemswerf building), a
decent car chase in a Lancer Evo, great fights (the
rooftop fight especially), Michelle Ferre was cute when she was pouty, and then there is one of my favorite moments in any Chan flick:
"WHO AM IIIIIIIIIIIIIIIIIIIIIIIIIIII??????!!!!!!!!!!"