Choosing a foundation paint color?

We bought a house last year and recently had it sided and the foundation is currently 3 different colors. 2 sides are white, 1 gray and 1 is still the cinder blocks. Our house is a tan/beige color and I was wondering if the foundation should be darker than the siding or lighter? I was leaning towards darker but have no idea what color. We are planning on getting 3 or 4 samples when it warms up and just trying them in a few places but I'd like to have an idea of what colors to get. I was thinking a dark brown or dark gray? Any help/ideas would be appreciated! Thanks!