What's your budget range?
Here are a couple of laptops I would recommend:
1) MSI GT780/783DXR :
http/www.msi.com/product/nb/GT780DX-GT780DXR-.html (or just go with the 680, which is cheaper.. and since you are going to connect an external monitor anyway..
2) ASUS G74SX : http
/www.asus.com/Notebooks/Gaming_Powerhouse/G74SX/
You can also look at Alienware laptops but they are generally not recommended if you are looking for something close to portable and... I really don't like the aesthetics of Alienware
If you can hold off for another month or two, Ivy Bridge laptops are going to be released with Kepler GPUs from NVIDIA and the HD7000M series from AMD. Both GPUs are in the 28nm technology.. so lesser power consumption and lighter weights...
If you are a resident of the US, you may also want to look at Clevo/Sager laptops.. They are usually cheaper than their counterparts. I'm not really familiar with these laptops though...