I just finished watching "21" on cable channel FX, and now "Rounders" is on - what a combo!
It occurred to me as I watched "21" for the second time ever that they're using genuine casino decks for the film shoot - right down to the canceled, round-trim non-index corners! Not a single deck in that film wasn't authentic, but none were uncanceled, either!
"Rounders" - at the opening scene table (and later against Teddy KGB), they're using Kem Arrows. At the table with the judges and professors, Bicycle Rider Backs in blue. Edward Norton's character, Worm, as he's leaving jail, same deck. I recall Bikes get a lot of play in this film.
Although I can't think of any specifics off the top of my head from movies, but I know people always get annoyed when I point them out.
I remember one time during the climax of an episode of "Law and Order", the crew walked in to see a bloody man brutally murdered on a poker table with cards scattered, to which I said "Those are Tally-Ho Crcle backs!" (Which got everyone angry because something important was being said, and they couldn't hear it.)
"Law and Order" was a legit New York show. Tally Ho, outside of magic shops, is a genuine New York brand, not sold elsewhere.
EDIT: I just spotted something in "Rounders", an old New York landmark that I've been to before - Billy's Topless! It wasn't half as sleazy as they make it out to be. It was actually pretty friendly and pleasant compared to most strip joints.
2ND EDIT: I also spotted a pack of Aviators when they were playing in the Greek diner - lots of USPC product placement in this movie...