Agree with what bit said...
I own a bunch of sample-based pianos, and Old Lady, as old as it is, is still one of my favorites. It's just a nice, warm, round, full tone in the lower velocity ranges, and still a little bite in the upper velocity ranges... Lots of character, but not "crazy old piano" character, if you know what I mean. check out the "moonlight low" and "moonlight high" velocity demos to get a sense of the available dynamic range...
http://www.sampletekk.com/proddemos/PMIOldLady/MoonlightOldLadyNormal.mp3 http://www.sampletekk.com/proddemos/PMIOldLady/MoonlightOldLadyLoud.mp3 It's just a good recording of a good sounding old piano, and I think has stood the test of time against it's "more technically advanced" peers. IMO.
At those prices, my personal recommendation for somebody on a budget would be to get Old Lady for those full steinway grand sounds, where piano is a major harmonic element to the tune... and 7CG Jr for those times where you need that classic, bright Yamaha grand sound to punch through... pop, rock, etc. Total $50... can't go wrong with that.
For punchy, bright tone I think the 7CG/7CG Jr. might be a bit more dynamic and
varied than Emperor... The Emperor sounds like a Bosendorfer, and that's the tone you get. Unless you're really looking for just that Bosendorfer sound, in which case, go for it! Though I admit I've never been a huge fan of the Bosendoerfer sound compared to Steinway and Yamaha and some others... :) I think both are bright in the mid to upper dynamics, but the Yamahas are less honky than the Bosendorfer, and therefore more versatile for a range of things. In EQ terms, I've always thought of the Yamahas being boosted in the low and high (especially) ranges, whereas the Bosendorfer is boosted in the middle, giving it more of a throaty, honky sound. Anyway... my $.02.