A PCI-E X-Fi Titanium series card will do the trick.

You can even use Windows 10 with any of the X-Fi cards and use Creative Alchemy to restore EAX functionality.... you just have to use the Alchemy configuration program to add each game.

Stay away from the xtreme audio series as those are the super cut-down.. not hardware accelerated wannabe versions of the card.

Awesome -- are there any disadvantages to the X-Fi series over say.. an Audigy 2 on a PCI board?

I don't think there are going to be any disadvantages.

Only thing I can even think of that would not even be a disadvantage in your case is that there are no DOS drivers.

The X-Fi will also not have 15-pin gameport capability, but that is a moot point with XP and up anyway since you could use a USB to gameport adapter if you really just had to use a gameport controller.

I have a Titanium Fatal1ty Champion, for my Final WinXP build, its a really nice card, No drawbacks that I've noticed.
Just stay away from the Titanium HD range as they dropped WinXP support