Well, how much do you want to spend?
I always go with Clevo laptops, in the US re-branded as sager, xotic PC has some, 15" version will cost you around $1700 for a pretty nice one.
Another bonus with these is that you don't get any pre-installed crap like you do with most mainstream brands ( Dell, HP, Toshiba , etc... ).
There are cheaper ones, but if you really want to edit video, if possible better to go with something in the $1500 + range
If you wanna pay absurd prices for a 17" one that has a desktop CPU and 2 nVidia cards running together, it may be about $4000+, but you can't beat that one at anything.
But, do some research, because screen options vary quite a bit and you wanna make sure you get a good one. Nothing worse than paying $2000+ for something like Alienware and the screen is crap.