Of the four, six, maybe eight truly classic cameras in all of photography's history, the stone classic of the past half century is a Leica with a 35mm* Summicron welded** to it. And a bag full of Tri-X. You can shoot color if you must, but it should be proper Kodachrome—none of that bourgois E-6. If it's le pur sang you want, go black-and-white. And none of that prissy "fine-grained" slow crap, either, which is really pathetic—any 400-speed B&W film you want.
Which Leica? The M6, probably, because there were lots of 'em, and because nobody knows how to guess exposures any more. You can buy a new equivalent in the current MP, but it costs so much and it's so precious that you'll be tempted to treat it like a collectible, like something fragile, which is the horrible fate of all too many Leicas. (Like dating a supermodel and being afraid to touch her.) It's all turned around backwards these days—like taking black paint, the el-cheapo blue-collar option back when, and making it into a high-cost "special" optional finish. Gag me with a leader extractor.
The new Zeiss Ikon (a.k.a. ZI) is the only film camera left on our list. In essence, as I proposed in my T.O.P. review of it, it's an improved Leica M. Although missing the Leica’s redoubtable Teutonic solidity and the panache of Leica’s continuous heritage, the Zeiss Ikon is a modern Leica copy with the improvements that many Leica owners asked for but that Leica couldn't give them because of, you know, the pur sang thing (it means "the pure blood"). The improvements are several and logical, and make the ZI the rangefinder of choice for users not already wedded to Leica—although, since it has the same lensmount and takes the same lenses, it could appeal to them as well. The result is a camera that’s ideal in terms of all of its various balancing acts, that has just the right feel, and that comes out being much more than the sum of its parts. And is just a pleasure to shoot with, too. If you prefer a 25mm or 28mm lens, don't miss the gaga 25/28 clip-on VF, which is just gorgeous—extremely expensive and worth every penny (get one of these for your Leica and 24mm or 28mm, too).
The Leica faithful (at least the ones who never use theirs) will have a checklist of all the differences that make the ZI worse than the Leica. Ordinary, normal, attached swing-open back, as opposed to the Leica's funky removeable bottom plate. Lighter weight. And it's (much) less expensive. But we happen to think all those are good things. If you agree, this might be for you. Or, go for that used Leica classic.
*I know, Henri Cartier-Bresson used only a 50mm. But you are not Henri Cartier-Bresson.