with 1600 bucks I would build a pc. You get exactly what you want and get the power your needing to play those games. But if you rather buy an xps then go for the XPS 630. I built one for you and this includes a 20inch monitor and its right under the 1600 budget
That would do whatever you need it to do and more. Unless your wanting to play FSX and Crysis At full rating then I would highly suggest going for custom and it may cost more than $1600.