I'd only buy a few cars. Because I figure If I bought more, I'd barely drive them and what's the point of having a car when you don't drive it.
My list:
1) 1970 Plum Crazy 426 Hemi Cuda convertible with white interior. (I hope one exists)
2) Top Porsche if the day (probably cycle through them every 5 years)
3) 2011 Camaro, fully gutted and customized making at least 800RWHP
4) Diesel Audi A8 (legal or not in the US, that'd be an awesome daily driver)
I'd also buy a Jet and a yacht. But I haven't researched those enough to know what I want. I just want the jet to avoid traffic and fly around the country for dinner on special occasions