Rented Hassys in the past for assignments. Very cumbersome and I don't like the form factor. If I'm going to "own" a large megapixel camera, I'd rather have one that has the same or similar form factor as my DSLR. Besides the Leica S2 is very well built (not saying Hasselblads aren't) and weather sealed like a DSLR. I'm sure the S2 line will only get better and it's like buying into Canon's ecosystem. Once you have a nice set of Leica lenses, you will only need to upgrade to better bodies when technically and financially viable. Hassys are only arguably better than the S2 for the time being. I suspect Leica isn't going to stop developing the line.
And don't forget the Pentax 645D, at â‚¬10k it only costs a lens more than a D3X, it's 40MP and weather-sealed, DXOmark gives it high regard, and there's a lot of lenses for it natively (not to mention adaptable from larger-bodies).
But then for a little bit more, â‚¬12k gets you a Hassy 31mp with lens.
cf the leica S2, as nice as it is and as much as I want one, it's double a Pentax 645D. Double that again to get to a Hassy 200MS, and even more still for the IQ180 back with no body.
If i could get my hands on any one of them, it's on a tripod for landscapes. Or if you want to print billboards with one, you'd still need a tripod and studio flashes. Handheld doesn't come into the equation (although with an S2, i'd be tempted).