I'm a guy, personally I think we just like them. It doesn't matter if its the latest Corvette, Mercedes convertible, jacked up pick uup pickup..or whatever. I think we just want to show off a bit. For example; 2 weeks ago I walked into a great deal on a brand new 2011 Toyot Tundra double cab, 4x4 full size pickup. Now, I had a 2009 Ford Ranger that had 23,00 miles on it..nothing wrong with it at all, but this brand nw Toyota was something that while any other time wouldn't have made much difference weather or not I got a new truck or not. Needless to say it was a deal that both my wife and I talked over and decided that this would be an ideal vehicle for family outings as my Ranger would carry 3 at best. So we went ahead and bought the truck, it is probably the nicest vehicle I will ever own, its big, its a nice looking vehicle, and I have gotten compliments from everyone that hs seen it. I also have a personalized license plate. Is it vanity or what, well maybe a little, but you see I am a licensed amateur radio operator (a ham radio operator) my license displys my radio station call sign. It lets other know that I am part of a group that provides emergency communications during a disaster, be it natural or man made, its not called the Amateur Radio Service for nothing, and its not just to provide communications when no other communications are available, but we also provide communications during marathons, special community events. On and on it goes.
For the majority of guys I think we do it cause we can, some may try and use that flashy car as a means to get laid,and in some cases it is a "penis car" but those cases I believe are the exception rather than the rule. We guys, and believe it or not a lot of gals just like a fancy, or a flashy car. Your mileage may vary.