THe requirements for the RC simulator should influence your choice more than the photo stuff.

I would say spend extra money on the screen (19 inch LCD, a nice one), and as others have said, consider getting a bigger camera, the hot ticket now are the through the lens systems, maybe $1500 but now you are in a different league from the small cameras.

Get the minimum requirements from the RC Sim vendor, then call Dell and let them set up a system for you.