I'm not so much picky about colour as I am about dogs whose pigment blends with the coat (So, black coat, black pigment... red coat, flesh pigment, etc.).
That being said, I like dogs with a solid colour base coat and white markings (Border Collies, Tollers, etc.), sable, fawn/mahogany with a black mask (like Tango, or Belgian Tervs), tri-colours, and some merles (but I am very picky when it comes to merles). Oh, and solids with tan/rust markings. I do generally prefer browns and reds over black, but not always. I'm not a fan of solid coloured dogs, with the exception of Belgian Groenendaels and Flat-Coats nor am I a huge fan of brindle or yellowish shades.