As Golfdriver said, it depends on the user. Hit the play store,install anything that looks interesting (you have 25GB to fill) and play. Uninstall anything you decide isn't worth it.
1 recommendation - I hate TouchWiz, so I use Nova launcher. 24 apps on the dock, 5X5 on the homescreen, and most of that in folders.
Put a screen protector on it. Even a cheap 2/$5 cut-it-yourself is better than scratching the screen. Get the kind of case that sticks up above the screen, so that if you drop it face down on a flat surface, the screen gets protected.
In a couple of months, they're going to release KitKat, 4.4.x as an over the air update. Everyone is free to do as he or she chooses, but I'm not updating mine until it's been out for at least a few months, and there aren't too many screams. (Reading about the 4.3 update to the S3 can give you nightmares.) And from what I've seen, KK doesn't really give you anything.
Have fun - it's nice phone. Just realized that mine still has Santa Android and a Christmas tree as wallpaper - have to change that.)