personaly all my music runs out my main pc to my mixing console then out to my super-audio hifi setup/studio monitors.
all you need is a standard sound card most folk want notic the difrance untill
A: all your music is riped at high sample rates and is not compressed to formats like mpeg layer 3.
B: you have a high quility hifi, a AC97 sound card will do most peoples needs in this situation
So what you have would be vnc on the tablet in to the main streaming pc.
The other PC stream out to your hifi amp, most have an aux input with RCA's.
Jobs a good'un