Bukkit

Skyauth

Automatically promote/rank-up players based on their total online time.

Allows admins to keep notes on players.

Enables hardcore style play. You die, you get banned.

Virtual chests. And workbenches!

Adds commands to your server

A simple api for creating plugins with custom projectiles using particles

Redstone defenses and tools

A better way of storing items.

A simple way to setup automatic payments and allowances

Spawns Either A Super Zombie Or Super Skeleton Where You're Standing

Scroll through paintings

SetSunny

Want to define your own help pages from files? Now you can!

The best chat channel plugin in Minecraft!

Makes jukeboxes auto-play, repeat, and loop through records in a chest.

iGates

LinksOnSigns

DeathSpawnR

A very simple plugin in where when a person is killed, their killer gets 1 heart and the killed looses 1 heart