So, the major change in 10.8 is the default restrictions on which applications can be installed, which can prevent installation of apps such as Microsoft Office and some other popular software.
To enable software from all developers, make sure that under ‘Allow applications downloaded from:’ the button next to ‘Anywhere’ is selected
I’d also recommend ticking the box next to ‘Require password after sleep or screen saver begins’ to prevent unauthorised use of your machine
In the FileVault tab you have the option of encrypting your whole system drive, this is great on a laptop as it will prevent access before even booting & will disable Target Disk Mode, make sure you have a note of the Recovery Key that is displayed when enabling this, as this will be the only way you could access the machine if you forgot your password.
The Privacy tab now has info on which apps have requested access to your contacts, location service info, access to Facebook, and the option to send diagnostic data to Apple