If you're a car fan and you find yourself in London, do yourself a favor and take the Tube over to South Kensington Station for a stroll. Get a cookie at Ben's Cookies and walk across the street to check out the new hardware at Lamborghini of London. When you're done, walk a couple blocks up Old Brompton Road and make a left on Cranley Gardens. Cranley Gardens is only a two-block street but be prepared to see dozens of amazing cars, all parallel parked on the street. The last time I was there, I saw everything from current-model Ferraris to original Jaguar E-Types and Series II Land Rovers.
Once you've seen the good stuff, head over to Harrods to see the ridiculous chrome-plated Bugattis with middle-eastern license plates that were flown in on a private 737 for a way over-the-top weekend shopping trip.