The thing I would do is make a backup of your machine via time machine or carbon copy cloner. then re-install lion and parallels and reboot and see if it hangs again, if it does'nt and everything works ok, you can restore your systems files and folders via the migration assistant and your time machine/carbon copy cloner backup.
I've never used Parallels myself, but heard about it being a bit tempermental, so it could be that, thats causing the hang. Sorry I can't be of anymore help than that.
Disabling spotlight worked perfectly for my macbook pro! Shutdown time went from unbearable (over 30sec) to about 2seconds. I use "alfred" instead of spotlight for a little while now, so disabling spotlight is a perfect solution for me. Thanks for the awsome tip.
Hope it works for you guys too!
Not sure what happened but I upgraded to an SSD and then installed Lion a few days ago and although my startup was quick, it took my MBP about 2 minutes to shut down. I did all the suggested preventive steps to no avail but after about the 4th or 5th time I shut down, the process was almost instant! I had heard that this happens sometimes when you load a new OS (I also loaded one game) that your MAC is doing things behind the scenes because of the upgrade and then those processes smooth out over time. I know...not exactly the technical advice I was looking for when I first read this but it appears to have some truth to it.