Just a little info you won't get from the self proclaimed experts@yahoo answers; the foot "twist" version you mention is present in all hard styles, even karate. It is an external method of striking which starts at the ground and continues to the end of the strike. The hips twisting while the feet stay planted is more of a soft style method which when done properly starts with the center turning and then the hips continuing the motion while feet stay flat and planted but only allow body turning in a limited/small amount at the ankles. Most fighting styles contain a few techniques that cross the hard/soft line in either direction. Keep practicing and it comes naturally after a few years. Always worry about the details because that's the difference between good and great. Ex. God is in the details. To be a Pro boxer or even a good boxer takes years of continuous practice just like any other skill or sport.

http://www.youtube.com/watch?v=9eR0Cn3ZF...

You need to read and talk less and do more actual training. Turning hips in boxing is like day one stuff and you do it for every single punch. Matter in fact just about every martial art worth anything turns hips with punches.

On the foot part. There are some schools where they want the foot flat while turning hip, but I think that puts a lot of stress on the knee joint. My suggestion is to turn the foot like you said while turning the hips. Key there is to make sure you turn it until the foot and the knee faces the front. Any more than that and you are sacrificing balance.

stop over thinking, and get an instructor, stick with one style.

at your level you are being too focused on insignificance details, like which is better which is more powerful. you worry too much about about things you shouldnt be at your level. focus more on your training every thing else will come with time. dont be in such a rush

And did you know that Asian styles do the same-thing, Including your precious karate, I guess not.

Hips is definetely important.