Currently, I train in a style similar to HST and what Dogcrapp advocates.
I hit each muscle group 3x - 4x per week; but the key is that the total volume on each group is the same as it would be if I were only training it once. (i.e. if one normally did one chest workout that included 12 work sets, now it would be 4 workouts with 3 chest work sets).
In this style, each muscle gets a primary day and muscle groups rotate. On a muscle's primary day, heavy, multijoint exercises are performed for that muscle; on secondary days, more single joint movements are performed (or multijoint at a lower intensity).
For me, key advantages of this style include that each set (primary or secondary) is intense. Face it, by your 15 th work set into a leg workout, you're not training at the same intensity as you were on your 5th set. I believe it also balances the body better from an athletic perspective and leads to more muscle overall muscle growth because muscles are stimulated (but not over-stimulated) on a more consistent basis than once a week training.