I'm going to have to say maybe. Both systems ride on how their motion attachments do. If one succeeds and the other fails, then the one who succeeds will be ahead by the end of 2011. If both fail, I think that PS3 will surpass 360, but not necessarily by 2011, as MS will announce the 360's successor. If both are successful, I'm going to have to lean to no, as the media hype behind Natal will get more of the "casual" people looking at it, and make more sales to them.
-dunno001
-On a quest for the truly perfect game; I don't think it exists...