Current favourite is a 17" N/M Stubben VSD in "choco" scrumpf leather. Close second is an 18" Hennig titanium sofa - only becuase I have nothing it fits currently!
My favourite has got to be my 16.5inch seat jumping saddle from Ebay, I love it! Was only about 130 including postage, but I can hunt all day in it and it helps me be secure when I'm jumping. It's medium width and is two-tone brown. Close second is my Shires dressage saddle, 16.5inch, medium width, and black