It all depends what quality of sound do you need/demand...? I just got GS today and getting ready to work with it, but from what I hear and read - GS is one of the best (if not THE best) way to get high quality sounds. Since you mention _solo_ piano, GS might be what you need. For playing around, Soundblaster Live and some decent samples will do... Again, it depends on how seriously you take your work. BTW high quality samples will cost you a bunch, too.
[This message has been edited by maugli (edited 01-08-2000).]