I'll ignore the bootleg aspect. Believe it or not, I say get Vista.
If you get Vista Whatever with the system you will pay less than half the price of buying retail. Then when 7 comes out you will probably pay 1/3 for an upgrade, less if Microsoft has some promotion to win back customers it lost with Vista. Basically, you'll probably end up paying a bit less for Vista and the 7 upgrade than you would buying 7 at full retail.
This doesn't apply if you get your hands on a legit Windows 7 OEM copy in the first place. Local computer stores are often nice enough to sell them.
FReepers rock!