All nations in ww2 made use of them, some are little known:
http://www.geocities.com/Pentagon/Quarters/1975/armcar3.htm
The Staghound for instance, who has heard of this one? It played a big part for the UK and was up armed throughout the war, used a lot in Italy. But it was designed and built in the US, who strangely enough never used it. There was even an AA version.
The Germans made huge use of them, culminating in the impressive 50mm gun armed Puma, 8 wheels, a top speed (forward or reverse) of 85 kmh. Unusually for a German AFV it was diesel powered. It also featured a second drivers position in the rear, usefull for a recce vehicle, with both six forward and six reverse gears and an all wheel drive.
The US also had the Greyhound and while not as robust as the Puma featured a handy 30mm gun and also had a good turn of speed.
There were of course many other AC’s used in ww2.