Everybody's a movie critic. Everybody has opinions about the films they've seen. But the one indisputable source of a movie's popularity with the public is the box office.

When it comes to movies on tape, the number of videocassettes sold is the arbiter of what's hot and what's not.The current issue of Video Magazine reviews the 10 best-selling movie tapes through 1987 from information provided by Video Marketing, an industry newsletter. There were some surprises on the list.

"Top Gun" was no surprise, taking the top spot of the top 10. This two-hour production about hot-dogging naval aviators, which was released in 1985, has sold 3 million copies.

A 1955 Disney production, "Lady and the Tramp," took second place with 2.6 million copies sold.

"Crocodile Dundee," a 1986 release, is in third position with 2.1 million copies sold.

Disney takes the fourth spot with "Sleeping Beauty," originally released in 1959. Sales of the videotape are anything but sleepy, with 1.8 million copies sold.

In fifth position is "Beverly Hills Cop," with a shade more than 1.6 million copies sold since its 1984 release.

Sixth spot goes to "Star Trek IV: The Voyage Home from 1986." It sold 1.6 million tapes.

"Indiana Jones and the Temple of Doom" is in seventh position with 1.35 million tapes sold since 1984.

"Raiders of the Lost Ark," the first in the Indiana Jones series, moved 1.3 million copies since its 1981 release to take the eighth spot.

In ninth is "An American Tail," Steven Spielberg's 1986 answer to Walt Disney that introduced another cartoon mouse, Fievel Mousekewitz. Fievel accounted for 1.12 million tape sales.

And in 10th position is "Ghostbusters," the 1984 release, which has moved 800,000 copies.