One thing I never see mentioned, but is apparently an issue is one of comparisons - for example, salespeople love to metion that artists prefer the 9' X concert grand over the 9' Y grand. But if you are looking at a 6 footer, the Y brand may make a much better 6 footer than X. i am discovering this - I am shopping for 7 footers, and notice that manuafacturers defintely have the *attitude* of a 7-plus foot piano being more for serious pianists and smaller pianos being more for looks. Some of this is marketing, but some you can tell by playing them. So definitely compare pianos that directly compete in the price range and size you are looking at.
Also, RachFan mentioned Larry Fine's book, which I wholeheartedly recommend. It has been invaluable to me in my research, and after playing a few pianos, I can now tell, from his descriptions on the book, what a piano might be like, and whether I would like it. His descriptions are that good. Plus it gives all the history of the various companies, and how certain models came about, etc etc. Definitely worth getting.
Anyway, have fun in your search! I am getting close to having to choose (I want one of EACH), but I'll have to pick just one. It's been fun looking (you can shop for free, ya know!)
Mindy