I might as well chime in that if you know what industrial motherboards to look for, you can even get Pentium 4-era 845P and 875P-based motherboards with fully-functional ISA slots alongside AGP 8X.
My current retrogaming system is built around such a board; it's kinda funny to have a 3.2 GHz Gallatin (P4 Extreme Edition), 2 GB of DDR-400 and a GeForce 6800 Ultra in a system that can house an AWE32 or AWE64 Gold and boot Win98SE with no problems (RAM aside, but there are fixes for that).
That said, the reason I would even bother with an AWE32 in a system that normally has an Aureal Vortex2 card alongside it is twofold: SoundFont support, and I want to figure out how to test the ASP/CSP in TFX. The Vortex2's there mainly for Windows gaming with A3D.
Okay, and I just remembered the third reason: Vortex2 SB Pro emulation + Unofficial 98SE Service Pack = BSoD, without fail.