Not just price. My wife who does not like video games at all, and hasn't played any video games in years, wants to play the nintendo wii. I have heard similar statements from a lot of people over the last few weeks. If Nintendo pulls in the casual gamers, like they have obviously planned to do, and can keep the more hard core gamers happy, they will come out on top without question. If they come out on top, more developers will make the "great" games for Nintendo's system.
All that being said, both the Wii and the PS3 have to still catch up to the 360. I have no question that the Wii will catch up quickly, but I don't know how long it is going to take for the PS3.