What's your favorite MCM sofa?  

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This is like mine, fabric though, keeping the cushions tidy sucks but thats just because there are feathers inside, thinking of padding them up with some removalists felt, was a very cheap find so bargains are there and I don't think you need to spend that much.
But if I could get what I really wanted it would be one of the sofas Mies designed for the Toronto Dominion Bank, I think Knoll produced them for a few years, in whisky brown leather of course, second choice would be a Citterio Magister, though it was done in the late 80's I think.
For practicality though something like a Jalk or Wegner with an exposed wood frame and loose cushions would be best though, cheaper and easier to upholster and if something gets stained you can keep flipping the cushions for a while. You might even find a damaged one for really cheap that could be repaired at little cost.

Killian
The De sede is surprisingly comfortable, although having said that I am not a sofa lounger I prefer an armchair and ottoman for slouching! I had the pleasure of living with one for 6 months and it surprised me how easy it was to live with and was not just a mad cap idea or center piece.

Mies van der Rohe Sofa
Heath, one of those sofa's Mies designed for the Toronto Dominion Centre is currently on 1st Dibs for $11,000; black leather. They are also in the lobbies of Westmount Square in Montreal; quite comfortable too!

a Kjaerholm pk31 is what I really want.
I like my old b&b italia battleship.

Ankh, I really wish you...
Ankh, I really wish you hadn't posted that, it provokes at least three of the sins.
It looks a little different to the pictures I've seen of others in pale fabric, not really suitable for public seating though.

Does late century modern count?
Roche Bobois cranks out a well made product.

Heath
I wish I'd known you love the Mies sofa. We just sold this one (and very inexpensively). It is a comfortable piece with the down filled cushions.
thehistorian, where are you located?

You sold it! How could you? ...
You sold it! How could you? Shipping over here would have cost a fortune anyway. Somethings not right here, those dont look the same as the pictures I've seen'. will post a comparison later.

Charleston, SC
I live in Charleston, a great city but a total wasteland for MCM furniture. I used to live in Atlanta, where there were a lot of options.