Anything but black, unless you plan to wash it every 3 days so it looks nice.
(I love black cars myself)
I would go with BMW anthracite:
There was an Alpina B7 at Otto's a month ago. Same color, but it was darker. I loved that color.
For blue, Mercedes 501 amazonite blue looks really nice. Used on SLR McLarens.
The plus side to going with black is you can paint the car at sections. But for metallic colors it has to be painted all at once to avoid mismatch.