🚀 go-pugleaf

>     1) Will D2 play on a PCI VooDoo 5 card, which I can get for about $40.

With d2_3dfx, probably, but not under Windows XP.  (I've only been able 
to get d2_3dfx to work under DOS and Windows 9x.)  The official 1.2 
version of Descent II for Windows 95 runs under XP (in the Win95 
emulation layer), but it runs too fast to be playable on modern hardware.

d2x adds OpenGL support to Descent II, so you can run it under XP with 
hardware acceleration in very high resolutions with lots of AA and AF on 
a GF4 card.  It's was kind of buggy when I last tried it, but it's 
getting better.

Glidos will let you run d2_3dfx under WinXP on any OpenGL hardware, but 
the graphics look kind of muddy and it doesn't perform well.  And unlike 
d2x, it's not free (though the Glidos/D2_3dfx combination is more stable 
and feature-complete).

>     2) Will D2 or D3 work on Win XP or should I partition my disk with a Win
> 98 portion on which to play Descent?

D2--see above.  D3 will run fine under XP.