My favorite romance movie. Any others as innovative as this gem?

It sort of depends on what type of movie you're looking for. I've seen a few romantic films that are very excellent and unique that are nothing like "Chasing Amy", for example, "L'Atalante" and "Sunrise: A Song of Two Humans" are two films that have been listed among the greatest of all time, and are two personal favorites.
If you're looking for a film a little bit more like "Chasing Amy", you could watch "Annie Hall". While they're both very different films, they're kind of similar when it comes to witty dialogue.
I'd also recommend the following romantic films:
"Harold and Maude" (which is my favorite film of all time)
"Punch-Drunk Love"
The Six Moral Tales series by Eric Rohmer
"In the Mood for Love"
"Groundhog Day"
"Eternal Sunshine of the Spotless Mind"
"Sideways"
"Love Actually"
"The Red Shoes"
"The Big Parade"
...and "The Life and Death of Colonel Blimp" (which I especially recommend, since it is a very underseen classic that is both very funny and sweet)

Easily my favourite smith film . " dogma" and " clerks " second and third .

High Fidelity is a good one.

Love Chasing Amy. Another great romance film is 500 Days of Summer.

Unique?

Sliding Doors
Eternal Sunshine of a Spotless Mind
Down With Love