Bukkit

Prevents users from exploiting glowstone to see through blocks

BlockSpawn

Changes a players health based on his XP level.

A plugin that allows players to disabled PvP for themselves.

One simple command for instant server info!

The Ultimate Flight Control Plugin

Sync - Providing all your data storage needs and more!

Give you an edited book when you join

It's just sponges.

Send and receive packages with items and more

Log all actions in your server.

ManHunt plugin from Dream's videos (even better)

CommandsFromFile - run commands fom a text file

Save Your Items on Death!

A new spawning system modeled after graveyard style spawns in mmo's!

DeGriefer

Place torches with your pickaxe!

Give someone a block or item for a certain ammount of time!

Give players strikes if they misbehave.

Control the speed of time