Unfortunately for you, he hasn't (as far as I know) elaborated on which of Cary Grant's movies you should watch.
If you're lucky, you may stumble across a blog post pointing out the better movies to watch, and which to skip.
If only there was someone who has watched a fair few of those movies and could point you in the right direction....
Arsenic & Old Lace
A movie with a novel idea. Little old ladies who help lonely old men end their [perceived] problem. With a man who thinks he'd Theodore Roosevelt, thrown in to boot!
Cary Grant is recently married and looking to leave for his honeymoon, when he discovers what his aunts are up to and he spends the rest of the movie trying to manage the situation.
A movie well worth watching.
Mr. Blandings Builds His Dream House
If you're looking for a Cary Grant movie to find a lot of wit and amusing lines, then this is it.
Mr. Blandings finds that his New York apartment is too small for his family and he and his wife decide to move to the country. They wind up building a new house and hilarity* ensues.
(*hilarity is a 1940's word, meaning: amusing)
I do wonder about the relationship between Mrs. Blandings and the couple's best friend.
Take note of the prices of things ($10,000 for a new house) and the nature of the world in that time. His daughter's school paper early in the movie is a sign of the doom (feminism) yet to come.
Another good movie.
I was a Male War Bride
A movie who's first half is about a French solider (Grant) and an American solider (don't care) who work together but are constantly fighting each other. If it had ended there I would have liked it fine.
The second half of the movie is not so good.
In the second half, after they decide to get married and move to America, Grant is put through ...situations meant to be amusing during his attempt to move to America as a "war bride."
The "fighting" in the first half of the movie is not bad, and if you like Grant's mannerisms, then the first half of this movie is okay.
The Philadelphia Story
A wealthy socialite prepares for her second wedding while interacting with her first husband (Grant) and a photographer.
Its the movie to see if you want to see the way Grant acts and interacts with others.
Its not the movie I'd watch for entertainment purposes though. Its not my sort of thing.
This is a movie about an actress in London (Ingrid Bergman) who is looking for a man. Cary Grant appears but it turns out that he's married.
This is the movie I'd watch if I wanted to emulate this actor's mannerisms and speaking. You get to see him start a relationship and direct it exactly the way he wants.
I quite like the surprise ending.
This is a good movie to watch through the lens of Game.
This one takes place in the South Pacific during WWII.
Grant's character wants to be left alone on his boat and to avoid the war. A man in the Navy "persuades" him to station on an island as a lookout for Japanese airplanes.
During the movie her winds up rescuing a teacher and her female students.
An entertaining movie; I like it.
The Bachelor and the Bobbysoxer (sp?)
A painter and his relationship with a female judge and her young sister.
Once again, its a good movie to watch for the Game aspects but not the sot of movie that I'd care to see again.
That rounds out all but two of the movies that I'm aware of Cary Grant making. (I don't remember Bringing Up Baby and don't remember the others title.)
It should start you in the right direction for watching movies by Captain Capitalism's favorite actor.
BTW Captain, since you and I seem to like many of the same movies (the above, the man with no name trilogy, and Cowboy Bebop), I recommend that you watch Exiled and Little Big Solider.
Update: A commenter reminded me of a few more movies: North by Northwest, Charade, and An Affair to remember.
North by Northwest was directed by Alfred Hitchcock and is good. Charade is fine too. And An Affair to Remember is in the running for my least favorite movie ever.