Which do you use for garrisons: Peasants or Town Watch?

[therother]

For my core cities, that are highly unlikely to face a significant enemy thread, I use peasants; I also always have an advanced army within a 2 turn "rush-in" distance if there is trouble. I always have a diplomat in each city as well, so if needs be, I'll just bribe the invaders. Although town watch are significantly better than peasants, I'd rather not have to fight with either, and peasants are better value per man in terms of garrison duty, as it's only numbers that count.

Out on the rim, however, I have armies of older front line troops (e.g. pre-Marius units), usually augmented with a few peasants if I need the Public Order boost. I usually prefer to have my best generals and troops in the field.