At my college bookstore (a Barnes & Noble) I saw the system I wish was in every bookstore in the entire world (yes, I liked it).

They had about 4 listening stations with touchscreen monitors that were basically running the All Music Guide. They also had audio for almost every single album I tried. So not only did you get the sample music, but you got the greatest music database on the internet to go along with it. IMO, that's the best system you can have. I literally spent about an hour on it. It was sooo good.