The actual color of the trichomes doesn't have much to do with it; the trichomes arejust off-white and a little yellowish sometimes. The various color hairs also vary greatly in number and color, and regardless of the color, the more hairs and crystals, the better.

Indica is darker buds, and sativa is also lighter, and more "neon" green. In this sense, the color can be indicative of the nature of the high, but not much further.

Also, indicas smell darker; you get weird scents like chocolate, hash, and cherries in indicas, whereas sativas can smell anywhere from fruity to lemony to earthy to almost like chamomile tea.