Actually, while I'm waffling on this thread, I should really give my answer to the original question.
I do think Leica rangefinders are special - I have an M6 and an M2. For me it's the solid feel and reliability of their precision mechanics, and that's something that no other rangefinder I've ever used has come close to. When I'm out shooting (usually in SA Asia), I can just sling one in my bag and not have to worry about mollycoddling it in case it goes out of adjustment, or bits fall off, or whatever (and that's actually moreso with the M2 than the M6 - I like and trust the feel of the M2 more).
But I don't approach Leica cameras with the almost religious fervour that some folks seem to, and I have other RF cameras that I also like and use. My Voigtlander Bessa R4A, with its wideangle VF frames, is an amazing camera - I often carry that with a 21mm lens and a Leica M with a 28, 35 or 50. But it's just not as solid, smooth and quiet as the Ms. That's not to say it isn't well made - it is - but I'd be less sure about cracking it over the head of any would-be thief who tried to take it off me than I would with my M2 ;-)
Some people have suggested the M bayonet is a great plus point, because it allows you to use a vast number of lenses going all the way back to the 1930s. And it is, but that's pretty much true with any M bayonet RF camera - including Voigtlander and Zeiss (though a small number of lenses won't fit properly on a Bessa - not sure about Zeiss).
Also, some people hold up Leica lenses as the prime reason to use Leica equipment. While I do think that modern Leica lenses are probably technically still the best around, some of the rest of the pack are so close that unless you're using very fine grain film and making big enlargements, most people just aren't going to tell the difference. Most modern Voigtlander and Zeiss lenses are, at worst, only a shade behind Leica lenses, and some have characteristics that are often preferred over some Leica lenses (one of my favourite ever lenses, for example, is the Voigtlander 28/3.5). And they're a lot cheaper (especially Voiglander lenses, which must figure amongst the best value optics in all of history). Personally, I mostly use Voigtlander lenses, but I also have several Leica lenses (my only almost-current one is an Elmar-M 50/2.8, and I also have a Summicron-C 40 which is a favourite, and a couple of older ones). I've done "real world" lens tests, using the kind of films I use (mostly Tri-X) shooting the kind of shots I like. And though I see some differences in contrast and tonality, I've never found an objective "best" under those conditions.
Would I buy new Leica today? If I could afford it I would (I'd buy a modern MP), but in my actual situation I wouldn't - new Voiglander or Zeiss would, for me, be better value for money than new Leica.