I have never understood people who willingly chose to use mobile devices as their primary editing stations. If your going to be editing photos or anything else get a real computer. For doing any real work a 30" 10bit display is pretty much a necessity.
I dont know of any laptop that comes with a 10bit display and its nearly pointless to edit your photos when your only seeing a small spectrum of the color in the image. Keep in mind that even an 8bit panel wont be able to show all the colors in the 8bit color depth. That means even if you are using an 8bit display your not seeing all of the colors even at JPEG level. The same goes for resolution, what exactly do you plan to do with all those 18-20+megapixles in your images with a 17inch display? I would sure hate to have to expand my image 1:1 or better on a display that small to edit my files

It seems like it would be a complete and needless waste of time.
Now of course I do have to use a laptop when im on the road for live updates. I work for a local website so i dont have choice. It sucks using one but when i can publish my photos within minutes its great! Two days ago i was at an event and i saw some guy editing his photos right there on the spot and i asked him if he was local. He told me he worked for the New York Times. Thats a great example of where a portable is perfect. But i sure wouldnt want to use it for more than a few quick updates to the web or of course for tethered shooting.
Im going to get a new one soon but im waiting for Ivy Bridge before i buy one. When i do it will be something with one of those Ivy Bridge quad core procs and other high end stats.
I sure as hell wont get a Mac, thats nothing but a waste of money. I build my own computers and i actually understand basic computer science. When ever i hear people talking about macs they always seem to use ambiguous generic terms that dont actually mean anything to explain why their some how better. Well i live in the real world and i need real reasons to buy my hardware lol. And no, OSX is not any better than Windows. Even if it was those computers would STILL be a rip off. They use regular grade parts in their machines designed to keep you from upgrading outside of what they sell you for the most part. You cant over clock with them even tho you should be able to, you cant get one with a an AMD proc, you cant get one with a 6 core SB-E proc from intel if you want, your just stuck with the S___ they offer and then you pay to much for it. They usually get hardware updates months after parts are already available for Windows and major software vendors usually release updates for their products on Windows before Mac. I could go but i wont. Apple is a rip off, wake the h3\\ up

And no, I dont give a crap about your "Well I had a bad experiences on a 500$ used Dell but ive had nothing but bliss on my 2500$ Mac" story so dont bother!
So if i was you, i would
wait for Ivy Bridge seeing as how its mostly an optimization for mobile computers in the first place, i wouldnt get a Mac at all and i would get a real computer to go with it or at least a good 30 inch panel to plug it in to. Ive Bridge is supposed to start appearing in a few months, it should save you some battery life and has decent integrated graphics so it could save you some money on that to.