Hmm...It's a tie between the original 300sl and the R129. the 300sl started the line and to this day is a breath-taking, magnificent machine. The R129 (late 80's to 2002) is the last of the true Mercedes-Benzes, as it actually was built to standard and not a price (which is more than I can say about the hideous lumps of malfunctioning plastic that passes for a Benz these days). Yes, the R107 is more of a classic at the moment, but the r129's had a much better range of engines (the m103 and 104 for sixes, the incredible m119 for the v8, and the brutal m120 for the v12), handle much better, are better equipped, and in my eyes, they look better.