Met up with a GF who just had a baby (6 weeks ago) and somehow we got to discussing visual stimulation, colors, and mobiles. Came home and did a little more researching and it seems that mobile objects should face flat toward the crib (which makes sense, duh), but most mobiles face the walls.

Most interactive (sounds, lights, etc) mobiles seem like an eyesore, but the aesthetically-pleasing ones don't seem that great for baby's development?
I also read b&w is too stimulating for a mobile, but babies like primary colors?

Any good recommendations or other advice for a crib/playpen mobile? Mamas - do you really recommend this as a "must-have" or just a "so-so" item? Also, did anyone try to DIY a mobile?