First rule! We do not talk about.......

Seriously though Alienware is way too overpriced so if you can stay away from them. It would be best to build a desktop but if you have to get a notebook just stay away from alienware. Brandname is all you are paying for with alienware. One of my friends ignored me a while back when he bought his alienware notebook for 1200. It cant even run FarCry 3

No, doesn't work like that.

Firstly the GPU needs to be equal or less in TDP as that is generally what the cooling system is designed for.
If it uses the MXM or AXIOM form factor it also needs to be the right revision.

Then expect to pay a premium.

Then... Don't expect it to be compatible with the refresh of the laptop the following year as they may change the dimensions of the card or even the interface a little bit.

THEN to continue adding salt into the injury... You will still probably be CPU limited in allot of instances, laptops just aren't that fast, even the fastest Laptop graphics cards are only comparible to mid-range Desktop graphisc cards.

But seriously, I say go with a decent desktop, buy yourself an AMD A6 APU laptop which is still very respectible performance/battery life wise and are cheap for your portable needs and can handle most games on low/medium (Even high if it's a 1280x768 resolution panel.)

You can improve the desktop over time to keep up with the demands of PC gaming, which is especially more important as we are on the cusp of a new console generation, so system requirements should take a bit of a leap. :)

Well. I would be interested to see if a laptop actually exists that could match mine or even get "close enough" even over the next couple of years. :P

Dolphin performs best with at-least 3 cores (CPU, DSP, GPU) and with a decent amount of clock speed. (Think 3ghz+)
Not many laptops fit that bill unfortunatly, Intel's mobile processors can turbo over that, but usually on only 1 or 2 cores, AMD's Trinity is horrible because of it's poor single threaded performance.

If emulating Dolphin is a must you want a laptop with a Core i7 3940XM or the 3920XM.

Most high end GPUs have a TDP of 100W. The upgrade GPUs often have the cooling kit on eBay that comes with it. So neither of these are an issue. The CPU limitation is always going to be there and obviously it means lowering some settings or upping AA. 

For most modern games, with a single GPU around desktop GTX670 level of performance, you'll be 95% GPU limited anyway.

http://pctuning.tyden.cz/hardware/graficke-karty/25994-vliv-procesoru-na-vykon-ve-hrach-od-phenomu-po-core-i7?start=16

There is no such GPU on the laptop side that even comes close to a GTX670 in performance.

I've seen plenty of Alienware users upgraded who already upgraded from 6970M and then to 7970M. For sure they'll be able to upgrade to 780M/HD8970M with a BIOS flash. I don't necessarily disagree with you with building a desktop PC but if someone really wants a gaming laptop, the upgrade path for the GPU is something to consider and it's for more easily accessible on the Alienware laptops.

You know, I dont think he's seen a top of the line graphics card and the amount of heat it generates and the sheer size of it.  Nor do I believe he really understands the economics of computer making.  If you pack the same power into a smaller package, the cost goes UP, way UP.  Laptop cooling is a joke, there is no way that much heat can exhaust through the tiny vents or much circulation can be designed into crammed space.  Physically and economically implausible.  Why is there even an argument here?

As far as why NOT laptop vs desktop, my take is desktop offers you the choice of a much much bigger screen much better positioned for gaming.  A mechanical keyboard offers much better feedback, and no, attaching a keyboard to a laptop is unacceptable.  Monitor will be 6-8 inches too far foward.

But id the OP insists on a laptop and price is of no concern, buying a premade bundle is going to be better than DIY.  DIY is in and of itself a fun game but I don't know of too many people who buy exactly the right parts and never tinker with it.  In the long run, like any hobby, it's a money sinkhole.

Well technically you can get a gaming laptop and connect it to larger external monitors if you wanted to:

http://www.youtube.com/watch?v=D9ggPOkdBIY

But like you said, to get a similarly performing laptop would cost thousands of dollars more. Well really it's impossible since no laptop is as fast as a Core i7 3770K @ 4.5ghz + GTX690, both components that can easily fit in a relatively small case. 

The other major downside of buying a laptop is very little flexibility in terms of resale value/upgrading. If you get a small PC case, you can always resell the mobo+CPU+ram and get $500 worth of new parts and reuse the PSU, DVD drive, SSD/HDDs, even videocard. You basically have a system that can continously evolve for the next 10-20 years at your discretion. With a laptop, sooner or later the entire thing is too slow and its resale value will probably be 1/6th of its original price in 3-4 years. 

The one specific case where I understand where a gaming laptop would absolutely work is if you travel a lot for consulting work or just have to travel all the time out of home. You can then use the laptop for gaming in hotels/airplanes. In those cases, a gaming laptop is absolutely a worthwhile purchase. For occassional lap parties, I just can't see any value in lugging a laptop since a gaming one will weigh nearly 10 lbs if not more. Chances are at that point you'll be brining it in a backpack or sports bag to begin with where you can fit a small form factor case with a handle as well. 

Nope he didn't, he said more tech savvy than you, which is far from impossible considering the posts you made in this thread.

This was completely uncalled for. Seriously, why are trying to turn this into something ?

Yeah, one top of the line gaming laptop = one good desktop + ps4 + Wii U + iPad. ....lol it's just very costly.  

You were trying to make him look arrogant by twisting his words. THAT was uncalled for, I just pointed that out.