Here is my situation. I am a photographer with a business just getting off the ground. I have an aging 2007 2.4ghz, 6gb RAM, 17" Macbook Pro w/ high-res matte screen that has been my workhorse for 4.5 yrs. It has been fantastic, but is showing signs of age (external and internal). My most recent purchase was a 27" iMac 3.4 i7 ssd with an extra screen as my office machine. That thing flies. I am now on the market for a replacement for my 17" MacBook Pro. I can't decide between a) another 17" b) downsizing to 15" or c) going ultra portable with a 13" Air. I do travel for my business and will need a machine capable of producing final images in a pinch on the road. I have talked myself into and out of an Air three times now and desperately need advice from some folks with some experience with these machines. My 2.4ghz 17" Pro is still capable of handling most of what I do. It is certainly is slower merging HDRs and stitching panos, but not horribly so... Opinions? Thanks.