On that motherboard, you won't be able to use PC/PCI or DDMA to route old PC IRQs and DMA channels to your PCI sound card. You'll have to use DSDMA, which is less compatible. Something to keep in mind.
As for which sound card is best, that depends mostly on whether you care about genuine OPL3 music. If you do, then get a Yamaha YMF724, YMF744, or YMF754 card. New-in-box YMF744 cards are still out there. The Aureal Vortex and Vortex 2's OPL3 emulation is flat. Like, literally, out of tune. The ESS Solo-1 and various SoundBlaster PCI options don't have true OPL3 hardware either, but their versions at least don't suck as badly as the Vortex.
If you would rather use wavetable MIDI music, the easiest realistic way to do that in DOS is with a card that has a wavetable header, since on-chip wavetable MIDI with these PCI sound cards doesn't usually work in pure DOS, just in Windows 9x. You can then use one of the many new wavetable boards coming out lately.