I'm looking to get a PB this summer (95% sure it will be the 15%), but I have one question: how noisy is the latest version? My mother has a 15" TiBook and the fan is on constantly - it drives me crazy! By contrast, I have a 12" iBook from work, and the fan almost never comes on - when it does, its only for a second or two. What experience have people had with the latest PB's? I just don't know if I can take that constant fan noise.