The 50's had great B horror movies, too, that attained some sort of cult status. While they weren't very good, they were entertaining. Four that come to mind right away are:

"The Creature From the Black Lagoon" - a laugher about a "gill man" in the Everglades.

"The Crawling Eye" - an omelette type monster with long tentacles in the Alps. Forrestt Tucker starred.

"The Blob" - starred Steven McQueen in this campy story of a big ball of jelly running amok.

"The Attack of the 50 Foot Woman" - really silly movie but had this awesome lookin' babe blown up to giant proportions!