I have either the same problem or a similar one. Power management is set to never sleep if plugged into house power. When the display is asleep and I hit the space bar the password window opens but when I enter the password it just gives me the spinning beachball and I have to hold down the power button to force a reboot.
I have been running Firefox and don't have Chrome on the machine. I have had both Firefox and Eudora freeze and force a hard reboot. When the screensaver is not running I can see what is going on as I keep Activity Monitor running and it is a progressive self-eating phenomenon. In the beginning I can pop open the dock and scroll Activity Monitor, but it eventually freezes these as well and I have to reboot. I can select Firefox in Activty Monitor if I do it quickly but it will not do a Force Quit.
I have noticed that when the problem shows up from display sleep, the clock is frozen at some time in the past, ususally around the time the display went to sleep and it does not change no matter how long you let the beachball spin.
I am going to set the display to never sleep for a couple of days and see if that does anything.
This is a new (one week old) MBA running Lion on a 1.8GHz i5 with 8GB and a 256GB SSHD
It is the replacement for my old MBA which was running fine on Snow Leopard.
Message was edited for clarity by: Doc Dougherty