It's time for a new work laptop, and I'm thinking about lobbying for a new MBP instead of the standard Dell POS. My only concern is that I'll be running in clamshell mode the vast majority of the time (driving a single 1920x1200 display), and I can't tell if either I should pay attention to anecdotal reports of excess heat and whining fans when running clamshell, or one model might be "better" than the other for clamshell mode. My machine should be running fairly lightly loaded most of the time, but on occasion I will drive it hard. The one thing I can say about the Dells around here is that they stay pretty quiet even when running hard and hot. I (and my neighbors) won't be happy if my fans are whining all the time at the office, though of course it would be OK on an occasional basis. Unfortunately there's no one around my office that runs clamshell mode to consult with, and I'm an iMac user at home, so I can't do any first-hand testing. So, would either the 13" i7 or the lower 15" model be more likely to run quieter? The quad-core is the main appeal of the 15" for me, otherwise the 13" would be perfect. Any thoughts? Or is this whole thing a non-issue?