John Coltrane / Rashied Ali Interstellar Space (never miss this one).
Smith/Blackwell and Cherry/Blackwell, Zorn/Graves, thumbs up.
Cecil Taylor/Mat Maneri - Algonquin
Bill Dixon/Tony Oxley - Papyrus (voll. I and II)
A couple of Joelle Léandre: with Steve Lacy and with George Lewis
Miguel Algarin / Albey Balgochian - Soul to Soul ... this is a last year output featuring nuyorican poet Algarin (the sole translator in the US of Pablo Neruda, as far as I know ... ) and a double bassist that shared the bill with Cecil Taylor, Ken Filiano, Charles Gayle and Steve Dalachinsky ... worth to give more than a spin, believe me.
Matthew Shipp did some interesting duos: with Evan Parker (saw them live, so don't miss them on record) and Rob Brown, as an example.
Tabozzivil, an impro/metal duo by young Turkish drummer Utku Tavil and young Italian guitarist Fabrizio Bozzi (here some excerpts from their records, issued in Italy by Setola di Maiale
I don't know if Arrington DeDyoniso from Old Time Relijun ever released a duo record, but he sometimes have some nice and firey plays with double bassists and kind of stuff, and they're worth listening, so if he's around, enjoy him.
.... and oh, one of the nicest, Han Bennink and Peter Brotzmann Schwarzwaldfahrt, recorded in a forest in Germany in the seventies. You hear birds, water, Han stumming on trees ...