I have a Ti 667 DVI that I use almost exclusively on my lap. I use a legal-sized binder under it with small pads that prop up the rear for better air circulation. The heat from the Ti is very tolerable with this arrangement. The fan hardly ever runs. Is there anyone who has used this model (Ti 667 DVI) and now has a new Al Book 15" who can compare the heat and fan use between the two models? I'm considering selling the Ti 667 and getting an Al Book 15 (1 ghz), but I don't want to be disappointed in the amount of heat produced. Thanks for any advice or information.