Ok having to pick just ONE color I'd say a solid grulla.
That said, I LOVE solid dun and buckskins. And I love dark bay pintos. And solid black silvers. And appies with a spotted blanket or a leopard, in any color (but prefer dark colors).
I also LOVE really red chestnuts with four stockings and a blaze.
I love a lot of colors! I'm not fond of light ones though, so not a fan of palominos or double dilutes. However, the DARK gold palos are gorgeous (and I do love light buckskins, but that's because they have the black points)
Jessi