Its style might not be for everyone, but the M6 convertible hits 60 mph in just 4.6 seconds. That means it'll only take a minute to dry your hair after you leave the beach. Of course, we wouldn't recommend tracking sand in a new, $104,900, V-10-powered BMW, unless your detailer is on speed dial. This is probably the least attractive car on the list, but we've run into more than one luxury owner who covets the 6 Series above all else. Loyalty — and the engine — put it in at No. 8.