First of all, I'd like to say the PS3 will undoubtedly be pretty cool, but unless the price is reduced by about $300, I'm probably not getting it.
One day, I'll get a Wii.
Some of the games on the 360 actually look like they'll be pretty good. And Resident Evil 5 would be a big reason for me getting one (even though RE 4 sucked).
So, personally, I think the one of the major things the 360 has going for it is that the PS3 is so expensive. And, of course, the number produced, like you said.