Wait for GS 3.0. There are supposed to be a lot more samples bundled with it, not the least of which is a better piano. GS 160, the current issue has a \'so so\' piano which is the only sample that comes with it.
The rumor is, that the current \'giga piano\' is so so because they used a Steinway that came out of a studio that did a lot of pop and country. The middle register is \'muddy\' which you may or may not like. I don\'t like it.
I know what you mean about convincing the \"accountant\" but luckily mine is pretty understanding.
I just took a look, and it looks like GigaPiano II, a Kawai this time is included with 3.0 (anything has to be better than that Steinway), \"BUT\" when I bought my GS 160 it came with a choice of 2 additional sample libraries for free (from a limited group of titles) as a promotion. I\'m guessing they will do the same thing for GS 3, if not right away soon after release, and you\'ll be able to backpeddle to get the freebies if you already bought.
BTW, I picked Dan Dean Solo Strings (Very good), and Maximum stregth Steel Guitar (barely usable), so as always do your homework on the samples and try not to buy on impulse. I usually scour the forums for the best advice, and not just go by the demos. Good luck!