CNC and legacy hardware

Something's that's been percolating in my head for a while...

While it's not going to be a problem for probably another 5-8 years,
what with all the old computer hardware that's about, but I've been
thinking about the so-called future of the PC.

It's my understanding that legacy hardware is going to be phased out in
newer stuff...namely, the legacy ports (serial, parallel, PS/2..).
While worth raising my eyebrow, it's not a problem as long as
PCI-parallel cards can be found.

What brought up this matter was recently, my brother recently bought and
installed a Nforce2 motherboard - touting it as being very stable and
fast - and I started dreaming of perhaps using an older Duron or XP for
my EMC-linux computer...when I start reading the specs of the Nforce2
board. No parallel port. "Not a problem", I thinks, and then I read
some more.

The Nforce2 he bought has integrated sound and video - and if I remember
correctly, all-in-one chipsets are a no-no for real-time usage
applications. I haven't had the time to test that premise, but I
understand why it would be true.

So what I'd like to ask the group is this: Which newer chipsets can be
used for real-time control? Which ones are best, and which aren't worth
a hoot?