I have always been an AMD fan and I have a dual amd 64 and I love it, I mean I dont know what could make it any better. My father is a P4 64 but I will always be a AMD fan.
I personally prefer, WMP. But when it comes to videos and codecs that are odd, The BSPlayer beats them all. My sister has a slow pc but with the bs player it doesnt lagg the video and audio when the plays it because it will crappen the video to keep up if the processor is slow.
I dont have a favorite yet till I play them and or take them apart. See what they really have inside of them. Microsoft is kinda stupid releasing theirs first before PS3 but ya know what I am not running that company!