Bukkit

Allows the user to change their name, and optionally with permission, names of others.

Achievement

Buy + Sell Items (For small servers)

Map .txt documents to commands.

Disables fall damage

Adds functions to AdvancedWarning

Adds the ability to warn and autoban players.

Easy anti-griefing options and a block blacklist w/ permissions

Adds colors and functions to signs

Forces helmet inventory slot to behave like a regular slot.

A fun team deathmatch type plugin. (Spout)