Bear in mind that, as long as you remove it from your machine, you are entitled to a fulll refund for any copy of Windows they ship with. Just quote them the first paragraph of the EULA, and if they won't play along, threaten to take it to court.
Edit: I did this with a Dell Vostro 1000 in the UK; I sent them a letter explaining that I wanted a refund, had wiped the disk, and could provide proof if needed. About a week later I got a phonecall from Dell saying that my card would be refunded with 5 working days. I got £35 for Vista Home Basic and £5 for Work 9. It's probably worth taking a couple of photos/vids showing you erasing Windows (dban is good if you have time, failing that either dd if=/dev/zero of=/dev/sda or even just removing the partition with fdisk should be enough.