The westerns were the number 1 source of movie catfights back in the old days, followed by women's prison movies and teenage delinquent flicks. These fights were the classic hairpulling, clothes ripping, rolling battles that got me (and apparently many others) hooked on this fetish. Some were filmed in color, many others in black and white. All were great.
Most of the better fights have been listed here (thanks to Myfordi, Maine and PatC), but there are lots more: San Antone, The Gatling Gun, Outlaw Women, Star In the Dust, Dalton's Women, Wild Women (made for TV), and many, many more.
I couldn't pick a favorite, but I would give special consideration to Marlene Dietrich and Una Merkel for their classic battle in Destry Rides Again. It was the first and it set the standard.
For your reading enjoyment check out this website:
http://popfiction.com/handsoftime/html/she/pistol/pistol.html