Earlier this month I bought a Lenovo X60 Tablet. This machine comes preinstalled with Windows XP Tablet Edition. Before buying it, I asked my dealer if it was possible to buy it without Windows preinstalled and he told me that there is no way to do so. Nevertheless, I bought it.

After the x60t arrived, when starting the system first, the Windows license terms *explicitly* said that I should contact the manufacturer (in this case Lenovo Germany) if I don't agree with the license terms to get a refund for the software while it was mentioned in the Lenovo specific EULA that I am allowed to use the hardware without the need to agree to the software EULA. So rule 1:
If you don't want Windows read the license terms before accepting anything!

Since the terms explicitly said so, I called the support hotline asking what to do for getting the refund. Of course the guy I talked to at the hotline was incompetent in regards of Windows refund and said "this is impossible at all since we do also sell systems without OS preinstalled". Since the license term said something else, I called my dealer, who happens to be an "official Lenovo partner", so he should know if there are any systems without preinstalled Windows. "Of course", he told, but only if you are a company that orders several hundred systems. So in short: the answer from the hotline dude was completely wrong for normal ed users.
But what to do about the "tax refund"? I asked the dealer if he had any experience with it and he said a clear 'no', but he offered to ask via his official channels since this might be a little more promising. He just wanted a short mail from me so that he a) does not forget it and b) has a good way to contact me. Okay, I wrote that mail and some days later I got an answer with a formula that I have to fill out which included the info what to do to get the refund. So rule 2:
Look for a competent dealer and ask him to help you with the refund, this might be faster than fighting the windmills yourself.

After sending in the sheet together with the license key and my banking account data, I had the refund for Windows XP Tablet Edition on my bank account exactly 2 weeks after sending the letter. The refund was only 30, but this is still better than paying for an OS that I don't want and having my Laptop appear in the stats of "sold windows copies". This was with Lenovo Germany. So here a short list of the things that were needed to fulfill the requirements for a refund:

1) The Windows license musn't be accepted, registered or activated.
2) Remove the license sticker from the hardware, make sure not to completely destroy it while doing so. Send it together with all CDs you got from them back to lenovo.
3) Add a copy of the bill for the system that includes type, model and serial number of the device.
4) Write down your ow data including bank account data so that they can wire the money.

I had to sign that I had fulfilled the requirements from point 1). It should also be possible to get the form directly from Lenovo, but my dealer was a great help with this. Keep in mind that this report is a) about Windows XP and b) from Germany. In other countries other laws might apply and with other versions of Windows the license terms might vary.

Another post (in german) I found about the Windows refund: Successfull report of Windows refund (german)

I hope this thread to be a) a nice list of other successfull refounds and b) an incentive for other users to try to get a refund.