Lots of favorites, depending on my mood...CadZZilla, Magnabeetle, Dream Truck, Tucker Torpedo, Mach 5, Coors Bandit, Batmobiles, or any of the cars from Talladega Nights would count. But this one was one of the first "fancy" diecasts I ever got, and since I'm a fan of both the design and movie, it holds a sentimental place:
I also have to give a shout out to probably the most expensive single car I've ever bought, if only because I'm almost mad that the quality actually justified the price: