I would suggest laying out a plan of attack. You need to think carefully before spending your money on getting stock in.
I think sticking with Nintendo for xmas is definitely the way to go. The trend from last year was that the majority of consumers were purchasing Wii and DS consoles and i very much belive that it will be the same case this year.
Having said that, i certainly think there is money to be made on selling games like Wii Play & accessories like the Wii Nunchucks & Remotes.