Well, What about the Soundblaster Audigy 2 NX?
On the Creative Homepage they say it supports soundfonts, so you could use a soundfont for midi playback, I don't recommend the free soundfonts, if I would pick, I would choose Synergi GS, it costs $17.99 and it sounds really great.

Here are the links:

Creative: http://www.soundblaster.com/products/audigy2NX/

Synergi GS http://www.samplebanks.com/

Greetz ,
Marcel