Select > Color Range is the way to go (fast and, I dare say, most semantically correct).
While you are in the aforementioned window, click your eyedropper tool on the little squares (
foreground color and
background color) in the
COLOR panel (usually top right) to sample a color you previously determined in HSB, RGB, LAB or CMYK mode (or simply picked from the palette).
edit - I was about to forget: in
Select > Color Range uncheck
localized color clusters and set fuzziness to 0 (although you probably figured it out) to select exactly that color over your whole image.