This bug has existed since the very first beta, I reported it to MS with the feedback tool but its still exists in the RTM.
After installing Windows 7 and booting for the first time, it asks you if you want to select a wireless network to connect to.
My wireless is a WPA2-PSK with a AES key.
It asks for the key to the network, but every time windows will say the key is incorrect no matter what.
Now the funny thing is I can copy the key from the key box into the clipboard, then skip the connection setup.
When windows finishes starting up I can click the wifi tray icon and paste the supposedly "incorrect" key into the key box, and it works!