Norton or AVG Free?

Never happened to me and I've used it on 98, 2000, 2000 Server, and XP, I've also installed it on a friend's Vista Laptop and it didn't popup for them.

Depending on how you setup the settings it will pup something up, but it won't be an ad. There is a setting for the updater to have it update whenever the computer starts. If this is ticked then you'll see an AVG screen pop up (not a browser window, part of the AVG program) and start downloading a file. This is it updating its virus database to make sure it knows what the latest threats are.

I believe this can be changed to always update on a time (Say Non every day that the computer is on) instead of at startup. For this setting to work, the computer must be on and into the UI (you can see your icons and desktop background). This means that if you have it scheduled to update at 12:00 PM and the computer is off (or you just pushed the power on button but it hasn't reached the GUI) then it won't update. Even if the computer reaches the GUI by 12:01PM it will no longer think it needs to update (because it has passed the scheduled time).

I think on-startup is best, but if the computer is an older one/doesn't have very good hardware then the latter would be better.

AVG Free is definitely better than Norton. Norton (internet security) comes with all this added stuff for *ware but you can get free programs which are just as good or better and take up less resources.
anti-virus - AVG Free
email scanning - AVG
website authentication - AVG Free toolbar for FF or IE
adware - ad-aware se
spyware - spybot s&d
malware - not 100% sure of a program thats focused on this but with windows defender and the aforementioned programs you will be alright
firewall - Zone Alarm Free (or even the windows one if you are cautious enough and have to use it)
online backups - get yourself an inexpensive dvd recorder and a spindle of dvds (or cd recorder and cds if you prefer)
performance tuneups - don't install norton
automatic updates - everything has this feature now, or the updates can be obtained through the program (except for with ZA)
parental controls - set your primary dns to open dns
identity protection and network monitoring - if you have an old pc laying around you can make sure it has two ethernet ports and install ipcop on it and install the add-ons advanced proxy and urlfilter and if you want even more protection you can set its primary dns to the open dns servers (make sure to get an account so that you can set the filters)
embedded support - the free programs aren't hard enough to use to require embedded support but if you do get stumped then you can ask almost anywhere for help

Why anyone would use Norton when AVG is out there is beyond me.

All recommended programs on computers can be found here.

I used to use AVG free until I got a free subscription to Windows Live One with my new internet.

Also, I used to have Norton, and it literally shut my internet down until I uninstalled it. There's no security risk if there's no internet connection, I suppose.

Norton.
I got 11 Year subscription for free