If you have the $$, get as close to the field as possible. Front row is well worth the $$.
The AFL gears itself towards a family environment now. It used to be a bit more rowdy in the older days when the arena was packed, but it's a great family experience.
Are you looking at a specific game? A game like SJ or LV should be great games to attend. SJ-AZ is one of the best rivalries in sports. Up the with any of the popular ones from the major sports.