Not too many people are using the parallel port with modern PC's. If you're using a motion controller, you can use a laptop, although a dedicated desktop is better imo. I've seen some people using those mini PC's that cost about $200 to run their control software.
I'd recommend UCCNC rather than Mach3/Mach4. It's cheaper, and better than Mach3. And Mach4 is an unfinished product imo, that's far too complex for most people.