I may be in the minority, but I love my Alienware. When I ordered mine, there was about a $100 premium over a similar Sager which I didn't have a problem with since I've always wanted one and the build quality and customer service is much better. If customer service can't resolve a problem, they send out a technician to your house the next day(assuming you have the warranty).
But if you're don't want to blow a ton of money, the M14x with the GeForce 650M is a good choice. 95% of the games I play are on all high settings and it plays them at great frame rates. Games like BF3 have to be played on medium/high, which is fine for me. The big thing for me is that it is extremely portable. I thought it would weigh a ton, but it's not bad at all.
You can get dual 675M's in the M18x if you want which would future proof you for a couple years. I'm pretty sure you can also eventually upgrade the graphics card in the M18x, but the M14 does not allow it.
Word of advice, though...if your heart is set on an Alienware, do NOT order them online. Call and get a representative who is willing to negotiate. My PC came out to something like $1,500 and I ended up getting it for $1,129 with no tax and a $200 gift card that I used to upgrade my RAM and get a SSD. You get MUCH better prices by calling.
Also, don't upgrade the RAM or hard drive when ordering. Get those separately because they're way cheaper elsewhere and they're both very easy to install.
Also, like Fox said, Asus ROG laptops are very good as well. Whatever you decide, good luck!
Not sure why there is so much Alienware hate, but being CAGS here, I would recommend people spend time over at http://forum.noteboo....com/alienware/
to learn how to buy Alienware for cheaper. If you are patient, you pretty much can buy a machine at 15-30% off depending on how much work/patience you have and this will put any Alienware laptop cheaper than any other company.
Read a lot of the messages there, but in general, Alienware doesn't cost anymore than any other laptop if you are patient and willing to haggle. I picked up an AW for around 30% off list new with accidental coverage and plenty others picked up their machines for 15%-20% with little work. One thing I will say is the deals do take some patience, but Dell reps are on that forum and it's not that hard to score some discount.
Also, Alienware is one of the few companies (if only) offering on-site support, if they mess something up, there are plenty of cases where they upgrade you current tech, etc...You do need to hammer at them to fix it, but there are enough cases of this happening.
All laptop manufacturers have issues, but if you take price out of the equation, then I think you might as well go AW for the better name recognition, easier resale value, on-site service, top tech parts.
I've went through this process myself a while back.