Bukkit

Touhou Player Enhancements

MultiCoders Plugin

Allows you to manage groups in-game, such as ranks or parties

Help Plugin, Customizable /help page!

advanced godmode, with lots of features

Ultimate Items Mod

Minecraft Anti-Cheat

MC-up

Plot System!

A centralized ban service for server owners with multiple servers.

Installs & Updates plugins automatically

CopyBooks

Greylist, a simple solution to griefing. Not an open server, nor a whitelisted one. Halfway in-between.

WorldBan

All sorts of TNT-related features, from bazookas to booby trapped chests! Perfect for war servers! Excitement +1

Players can call you fast when you're not even online.

Its Just a Dustbin :P

On demand player information

TheFishingGames

Filling Your Server With Kick-Ass Commands