Check this theme out. It's really, really cool. Kinda like an updated Windows Classic. Not at all toy-ish and very suitable for day to day use. To those that don't know you'll need either Style XP (keygen easily found from astalavista or the UXTheme patch, available at www.lightstar1.com, to use it. I recommend the latter.
This and crystal are the only visual styles, i've found, that i really like.
If anyone else has favourites please post them.