Hi all, I currently own a mid-2010 13" MBP fitted with an SSD. I use it a lot on my lap, and heat is an issue. I am considering getting a new machine, either a base level 13" MBA, or an 8 GB 13" rMBP. My question: Which would generate the most heat for my use (which is mostly MS Office, web browsing, sometimes youtube videos)? Would heat be a problem with either? Would the difference in heat from my C2D machine be significant? Thanks in advance.