That's a hard one Florian! There are so many good ones. I think most of mine come from The Maltese Falcon:

"When you're slapped, you'll take it and like it."
"The cheaper the crook, the gaudier the patter."
"A crippled newsie took them away from him. I made him give 'em back."

But I like this one from High Sierra too:

"Of all the 14 karat saps. Starting out on a caper with a woman and a dog."

And of course, from The Big Sleep:

"Get up, Angel, you look like a pekingese."