Ed Bott over at ZDNet is really on top of things because he noticed that you don’t have to enter in a product key when installing Windows Vista. If you simply leave the product key field blank and try to continue it will ask which version of Vista you want to install.
You will have up to 14-days to supply a product key after you have installed any of the Vista versions, so now you are can try out different ones to see which best fits your needs. Remember that if you select the wrong version for the serial number that you have you will need to reinstall Vista completely, so if you already have a serial number then I highly recommend you just enter it in while performing the installation.
This should also help satisfy those people who didn’t receive a product key for Vista Beta 2 but they want to test out the Vista RC1 that was just released the other day. I would imagine that Microsoft should be able to get new keys out to the public within two-weeks which is how long you have before Windows expires.