IMO there is only ever 1 option.
soundblaster audigy 2 zs in a PCI slot running kxproject (google it) drivers.
I have my PC in boot, giving me a full sound processing active (i.e. 6 channels out, 2 tweets, 2 mids, and 2 subs (Summed)), time aligned, and EQ'd. I run straight from PC to my amp (3 stereo wires) - a McIntosh mc440m ricpf ;), which then directly drives my McIntosh speakers - no passive x/o required, so more headroom.
The SQ is better than my old system of a Pioneer DEX-P1r - which is a very good headunit.