Scott,
You can start by doing a free test.
Try the free standalone sfz soundfont player
with the free Another XG soundfont.
Make sure you configure sfz to ASIO.
Also have MidiYoke installed on your computer
to connect sfz to other programs like
VanBasco. The above setup should use up less CPU than running Cakewalk hosting sfz.
Playing XG midi files is going to be tricky part.
If all your midi files were in GM/GS format,
running VSTHost(http://www.hermannseib.com/english/vsthost.htm)
hosting HQ Hypercanvas would
be a very decent quality playback setup(I have tested this setup MidiYoked to VanBasco and it works great)It would probably also use less CPU than Cakewalk hosting Hypercanvas.

[This message has been edited by Vquestor (edited 03-28-2005).]

[This message has been edited by Vquestor (edited 03-28-2005).]

[This message has been edited by Vquestor (edited 03-28-2005).]