Microsoft could really push Natal providing it has some games ready for the launch and win over consumers. Developers supporting the Natal Project is key for its success.
Possible Natal games could include: Natal Fit, Natal Sports, Natal Play, Natal Fable, Natal Halo, Natal Let's Sing and Natal Let's Dance. Sounds good to me.
Copy Nintendo's generic naming of games with "Wii" in the game's title. If "Natal" is in the name it could be a seller and providing that Natal is reasonably priced, bundled and the Natal games are reasonably priced as well.
Some Natal games could be fully downloadable on XBox Live- I do not see them being as big on content as full retail games.