One problem I have with American Brown Ales is that they're either overly sweet...or watery. I've tried about 15 different browns in my travels, so I'm not an expert by any stretch. But then again, it's not a style I normally seek out.
My favorite is Real Ale's Brewhouse Brown. Not overly sweet. Spicy with tons of raisin, fig, even a little banana... and a dash of brown sugar and black tea. A silky, yet light mouthfeel with sharp carbonation. Concentrates on the malt like a brown should. Almost complex. Closest thing America has come to a good Quadrupel like Abt 12 or Rochefort 10, and made right here in good ol' Fort Worth TX.
An honorable mention is Anchor's Breckle's brown. This has quite a bit of fruity hops, making it a bit unorthodox in my limited experience, but still superb.
Beer fans...what's your favorite American Brown Ale?