Hi,
After reading this thread, I though I should share my experience. I've been a PC guy all my life and I wanted an Alienware for many years, so 2 months ago, when my trusty Dell laptop started to show signs of age, I decided to threat my self with a brand new Alienware m15x with all the bells and whistles that comes with it. The minute I opened the box, I knew I made a mistake. It's not that it isnt a great laptop, imho, this is the best gaming machine money can buy these days, but it was A LOT bigger and heavier than I expected. I had read hundreds of threads and reviews so I knew it would be like that, but having it in your hands is another story.
Anyway, I started using it and while I was very pleased with the great performance of the beast, I just couldn't fall in love with it. A few years ago when I was still at school gaming all the time and going to lan parties, I would really have enjoyed an Alienware, but I'm now more a casual gamer (in fact, all my gaming is on PS3 now, except for Starcraft II and some other stuff occasionnally).
I also own an iPhone 4 and since I work as a developper, I'v been lurking the iOS development for a while now so my interest for mac has been growing in the past year.
So after one month of using my Alienware, I decided to sell it. It broke my heart to sell the beast that I dreamed about for so long, but it just didn't fit my needs nowadays. I dont carry my laptop around so often, but the m15x is not really portable and I dont play enough on my computer to justify it.
I quickly sold it without loosing too much money and started shopping for a MBP 13", but I quickly realized that it is not really a good time to buy it, because right now, the 13" has some really outdated hardware (c2d, low res screen....) so I'm now back on my good old Dell m1330 laptop, but I will be buying a MBP 13" whenever the new generation comes out. (probably around spring from what I understand).
In the mean time, I still wanted to start gaining some experience with OSX and iPhone development, so I managed to transform my m1330 into a so called hackintosh and I must say I'm really surprised by how well it runs. I'm enjoying OSX and all the mac environment and I already started developing my iPhone app.
So this is my story... hope it helps!