... to supplement my iMac, because all the coolest software (especially freeware) is only written for the PC.

I know there's a way you're supposed to be able to run Windows software on the Mac (Bootcamp, is it?), but my 6-year-old iMac has always been laggy as it is, and I want nice, smooth frame rate for flight sims, like FSX, X-Plane, Orbiter, Vehicle Simulator, FlightGear, etc.

Ideally, I want to get both a desktop system and a laptop, but I hear there are all these variables and combinations in the way of components to mix & match, like motherboard, CPU, graphics card — hell, you even have to get the right fan!

Any gamers out there who can recommend a system that will give me a good virtual experience without costing me an arm/leg?

Thank you for your cooperation. Good night.