Hi Folks, I'm still running a circa 2007 white macbook MB062LL/A. I've added up to 3GB RAM and Apple replaced the logic board 2 years ago for some long-ago problems. The battery was replaced about 1 year ago and I had to tape up the cord to prevent the cat from eating it. It still runs on snow leopard, but can't get most of the benefits out of the newer OS. What are the chances I can sell this thing? At what price? I'm a bit torn about what to buy next. Part of me wants to wait and see if there is an Oct release of a 13" retina MBP, but I'm fairly certain that the 13" air will be fine. I assume the rMBP will be in the $1600 ball-park for a base model (4GB ram, let's predict discrete graphics). How would you compare to a maxed 13"air? Is i7 really worth it for a scientist who wants to run parallels, and does some image manipulation in photoshop? Anything else that I should think about would be appreciated. Thanks.