http://www.powernotebooks.com/PowerP...-sys-4273.html
http://www.youtube.com/watch?v=3UKHj...layer_embedded
The powerpro is the model I use. It works great, and has better specs than the MSI you listed. It's the same basic machine for slightly cheaper.

http://www.powernotebooks.com/Sager-...-sys-3726.html
This one is highly recommended by the users at notebookreview.

Either of these machines will get the job done. They're a bit on the heavy side but I know they'll play the game well.

I typically link these two machines any time a post like this comes up, that's because they get the job done.

You'll want more than a 555m btw, but if you are fine with a 555m, I'd suggest:
http://www.powernotebooks.com/Sager-...-sys-4047.html

I've owned a couple of alienwares and I never found their performance or durability to be satisfying.