"Retro" cars . . .
Like, from most to least: MINI, Mustang, Thunderbird, Solstice, Camaro (if it makes it into production relatively unchanged). I think MINI and Mustang are just brilliant. The only reason I didn't buy a MINI is that the nearest dealership is almost 1-1/2 hours away. The Mustang almost makes me wish I'd waited 2 more years instead of buying the L (almost). Love the T-Bird's looks, but realized after a test drive that I couldn't put up with the "flexible flyer" chassis and the negative headroom (at 6'1", I found my head pressed against the soft top even with the seat all the way down). I'm no fan of G.M., but I think the Solstice and the Camaro concept are really good-looking cars. I'd consider owning a Solstice.
Lukewarm: PT Cruiser, HHR, SSR. Used to like the PT cruiser, but now that they're all over the place, my enthusiasm has cooled. HHR is a more angular PT knockoff, and the SSR is a poseur pickup.
Dislike, from most to least: 300, GTO, Magnum, Charger. I think the 300 looks like a pimp's car -- wouldn't be caught dead in one. Sleepers are OK, but the GTO's styling puts me in a coma (I don't really consider its styling to be retro, but someone brought it up). The Magnum bears too close a resemblance to the 300 (it's more of a wagon for a pimp with kids). The Charger isn't too bad, but it suffers from the same overwrought, caricature-like styling that Chrysler started with the catfish-faced Ram.
Your mileage may differ.
Oh, and a friend of mine who is a big G.M. fan <I>did</I> test drive a GTO, and he just didn't like it. He found the straight-line acceleration to be basically its only redeeming feature.