Okay im needing to buy a powerbook g4. im a graphic artist so i need it obviously. i can only afford, right now, the mid model...550mhz combo drive not the 667mhz. i have heard some talk about the 500mhz actually performing better then the 550. for those who do have a 550...how is it? are you happy with it? for those that have the combo drive...hows that? are there any problems with the heat and or the speed? any under buffering? now im really digging the combo drive for obvious reasons but will it be a hassle for me in the long run? should i instead purchase a better external one and go with the 500 model? i know thats a butt load of questions but its cool if you can only answer one. i dont mind. give me anything you can spit out.