Special pricing does vary from store-to-store, and I honestly think it's not a matter of Apple policy as much as it is meeting per-store sales goals.
At my college store, we had pricing on Powerbooks below Apple's standard educational price, and I heard reports of our local Apple store matching our price at least once.
The Valley Fair mall store here in San Jose has been honoring educational discounts on everything up until now... but many people have told me that they are adamantly refusing to sell Panther at anything less than $129, at least for the kickoff. People have also told me that the Valley Fair store employees are jerks, and the Palo Alto store is much better. This is just me passing on what I heard, I've never actually been inside.