Here’s a link to the “About Google Pack” page. Looks like you at least get something extra with Google Pack.
The version of Norton Antivirus in the Google Pack includes 6 months of protection updates that enable the program to identify and remove new threats. If you’d like to continue receiving these updates after 6 months, you’ll need to purchase an update subscription from Symantec. Purchasing a subscription is optional.
There’s also a Google Updater to keep your software nice and fresh.