You DO NOT want live creepers, unless your prepared to have you major cities filled with craters and bunch of lazy and/or poor people who don't care and/or can't repair the creeper damage.
I know from experience.
If I recall correctly, the issue of having live creepers was to be bundled with having some form of mob protection program, whereby mobs would not spawn or be allowed within city limits. I recall one mod that allowed players to build a mob repulsor beacon that would keep the baddies away at a certain radius... Sadly, I cannot recall the name of it. There's also a slew of Bukkit zone protection plugins like EpicZones, Residence, and Regios that can despawn mobs or nerf creepers within certain zones only, making the remainder of the map fair game for crater creation.