For folks booting Ubuntu (or actually any 3.5+ kernel) off an SSD and have not disabled the asus-wmi module, you'll be seeing the kernel panics (the ones with the caps lock key flashing).
I've found a workaround which seems to work for me. Type this in a terminal:
This basically disables btusb during the modprobe stage in the bootup, and insteads inserts the module at the very end of the bootup.
echo "blacklist btusb" | sudo tee /etc/modprobe.d/blacklist-btusb.conf
echo "/sbin/modprobe btusb" | sudo tee /etc/rc.local
FYI - btusb is a Bluetooth USB module, which seems to be having a race condition in timing when booting off SSD causing kernel panics.
Let me know if this works or does not work for you.
All I could find was based on the info in the bug report #1041883, one of the folks mentioned about the asus_wmi_rfkill_init() function which seems to be handing the RFKILL switch i.e Fn+F2 key (for Wifi, BT, 3G, etc.). So I tried disabling few modules during the bootup corresponding to these and finally found out a very highly likely module causing the problem.
More info here: