I've been using a regular laptop of 4 years with Windows and have decided to switch to MacBook, but I have hard time deciding which. I need to carry the laptop with me, and my current 2,1 kgs with 10 mins of battery life isn't helping, so I'm considering MBAir. I want to upgrade it to i7 and 8GBs of RAM, because I use the PC with Photoshop CS6, iTunes and up to 150 tabs, all at once, with which my 2.6 gHz i5 laptop with 4GBs of RAM as a lot of problems. But I've read that i7 shrinks the battery life considerably, which makes me reluctant. Again, I watch a lot of movies and use Photoshop frequently, so I'd appreciate a Retina display, but I'm doing okay with my current 1366x768 with AMD Radeon, so yet again I'm reluctant. An Apple Store employee suggested a rMBP for my technical needs, but yet again, since I can only afford the low-end model, I'm not quite sure about the performance, not to mention the 1,6 kgs. 12" rMB is winking at me with her Retina display, 0.9 kg and 13.1 mms, but I'm afraid the lack of ports (even 3 USB ports don't suffice at times!) would drive me crazy. Besides, despite the lack of reviews, 12" rMB seems to be notorious for her performance. In my local Apple store, 12" rMB, 13" MBA with i7 and 8GB and 13" rMBP all have the same price tags, in case that's relevant.