I've lived in both, but I grew up in the Subs of A-Town Colorado, (Aurora, cheesey nick name eh'?)but I have lived in small urban towns for fire jobs, one of the perks to wildland fire fighting. I can def say that both have their advantages.
Small rural towns:
Everyone knows eachother and everyone looks out for everyone else that lives there.
Peace and quiet & beautiful landscapes
Your dollar spent is circulated through the town (no Wal-Mart effect)
Food is almost always better (low in variety, but consistantly good).
Larger Urban towns:
Easier to be independent
Easier to access resources (food, businesses, people, etc..)
Larger job pool (more options for careers)
Larger Gene pool (more members of the oposite sex to choose from) -back fires when STDs come into play-
Variety (smaller towns usually tend to have the same thing, over and over, and over again).
What you grow up in you will most likely favor however, its natural to feel a need to rest in your roots.