To enable some users who need to switch back and forth frequently, a small usability item would be to allow the guest OS (i.e., Windows) to re-map the cmd and ctrl keys. Therefore, the key-combination for window's based activities (e.g., copy, paste) would be the same in either OS. I think this could be easily done with an additional "parallels tool".
There is already some discussion about this in a similar thread. Follow this link: http://forum.parallels.com/thread1615.html
