Thinkpad Laptop When Is The Best Time To Buy A Thinkpad Laptop?

When is the best time to buy a Thinkpad laptop? - thinkpad laptop

I freshmen my studies and I want a new laptop.

I like the ThinkPad T400, but I do not know when the price is cheaper?
I buy one on black Friday or Christmas?
I buy for Windows 7 is released, or now?

and if the next generation of the T-series, if it exists.