Shitkickers were originally workboots. Eventually they gained the name shitkickers because they were the type of boot one would wear if one were to go out an purposely look for a fight (i. e. kick the shit out of someone). Most common brands would be Doc Martens and Altama. (And where is Feraliminal whne I need her??) The fashion for skinheads to wear such boots got so popular at one point when I was younger that there was talk in Sweden of banning them or figuring out a way to prevent non-workers from wearing them, on account of all the violent acts that were commited using them as a weapon.
As for myself, I have Altamas, because they make for excellent boots for an archaeologist. They also serve as great "anti-presonnel weapons" (no military man in their right mind would bother hitting on a chick in combat boots...unless they're fresh back from the desert, of course), are very comfortable and otherwise utilitarian, and in combination with my Mjöllner and my bomber jacket, they scare the hell out of the soccer moms at my kids school. If nothing else, if someone tells my kids "Yo mama wears combat boots", my kids would get a good laugh.