Any movies like this?

A very closely related film is 'Gambit,' with Michael Caine and Shirley Maclaine. In the same genre, very entertaining, great performances and a great heist. It isn't on DVD yet, but if you can get ahold of the video or catch it on TCM, it really is worth it. Also the original 'The Italian Job,' also with Caine. 'Charade'-more of a Hitchcockian thriller, but similar, with Audrey Hepburn and Cary Grant.

Yours is a capricious nature. Do you always blow hot and cold like this?

The original version of The Thomas Crown Affair with Faye Dunaway and Steve McQueen. And I second Charade!

You might enjoy "Hot Millions" (1968)
• Peter Ustinov
• Maggie Smith
• Karl Malden
• Bob Newhart
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and a cameo by
• Cesar Romero
that steals the show with only two brief scenes.
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"Dog Day Afternoon".Really good movie starring young Al Pacino.

I, too, vote for 'Charade", "Gambit" and "Topkapi" especially.

Rough Cut (1980)
starring Burt Reynolds, Lesley-Anne Down and David Niven
IMDb synopsis:
A romantic comedy with action and suspense. Two sophisticated jewel thieves join forces to steal $30 million in uncut jewels. Despite a continuous exchange of quips they eventually become romantically involved.

The Hot Rock (1972)
starring Robert Redford, George Segal and Ron Leibman
IMDb synopsis:
Dr. Amusa approaches Dortmunder about a valuable gem in a museum that is of great signifigance to his people in Africa, stolen during colonial times. Dortmunder assembles a crack team of cat burglars and hatches an elaborate plan for stealing the gem. Despite their care and experience, circumstances and plain bad luck keep the gem just out of their reach.

Lassiter (1984)
starring Tom Selleck, Jane Seymour, Lauren Hutton
Lassiter is a handsome jewel thief operating in London in the late 1930s. One day, he is arrested and told that, if he wishes to avoid prison, he must break into the heavily guarded German Embassy in London and steal millions in gems.

There's another that slips my mind.

This one isn't in the same style, but it's a must-see heist film: "Rififi" (1955).

EDIT: I remembered!
11 Harrowhouse (1974)
starring Charles Grodin, James Mason, Candice Bergen
A small-time diamond merchant jumps at the chance to supervise the purchase and cutting of a large, first-class diamond. When the diamond is stolen from him, he is blackmailed into pulling off a major heist at the Diamond Exchange, located at 11 Harrowhouse.


*** The trouble with reality is there is no background music. ***