*I don't have time to do more research, so you'll need to look yourself. At your budget, here's some tips:
1) Windows 8 64-bit (not Windows 7)
- get START8 ($5) as well if you wish and play with the settings, learn how to boot directly to Desktop etc..
2) Screen size (17" or smaller?)
3) Screen resolution should be 1920x1080
4) Graphics? (probably the biggest expense)
5) CPU: Definitely a 4-core Intel CPU of the new Haswell series (i5-4xxx)
6) Quality (good customer feedback and reviews)
Another option is to just buy a $400 laptop for portability and build a small DESKTOP setup. You'd probably get as much or MORE performance by spending $1000 building a desktop as compared to a $1400 laptop.
Get a monitor that has HDMI (HDCP) input and DVI (or dual-HDMI), buy an inexpensive laptop and a Sony PS4 gaming machine and have both attached. Probably not interested though but it's an option.
Laptop + Main monitor (23", 1920x1080) is a nice idea to have a 2nd screen for the laptop. I did that in College so I could have two different programs open such as Word Processor and Browser.