Global Plugins

Sub category Permissions
zPermissions carving it up in the permissions class of plugins. zPerms is keeping it real with SQL support, light memory usage, and general sexiness. zPerms is killer when used in tandem with the Bukkit permissions.yml.
Group Manager Essentials Group Manager is a implementation of permissions. It allows you to set up permissions for groups, and add users to these groups. The result is you can have multiple tiers of access to commands. This is useful for most Minecraft servers, as it lets you build a community, without it you struggle to balance the right number of admins with users.
PermissionsEx (PEX) is a new permissions plugin, based on Permissions ideas and supports all of its features. But PEX is more! It offers different backends, powerful ingame management, fine grained restrictions for world modification.
Sub category Admin plugin
CommandBook is shooting down Essentials on every front. With plenty of config options, light memory usage, and selective enabling of features, it's all the good of Essentials without any of the bad.
Essentials Because it is the essential plugin for all server's
Sub category World Management
WorldEdit is probably the greatest plugin that was pretty much made solely for abuse of all time.
WorldGuard Because who wants creeper's blowing up your Building, Also for the
Sub category Chat Managment
SimpleChat is hot like fat stomachs with bold ripples. Nothing has been able to make chat more handsome since HeroChat (good night, sweet prince).
Sub category Player logging and ban management and AntiGrief
BanManagement is the final and very best reincarnation of MechaHitler. Rule like a true dictator!
HawkEye is killing it in the logging department, cooking up some of it's signature, sick INGSOC swag.
NoCheatplus Because who like's cheater's
LogBlock For finding these griefers that no one likes
AntiCheat helps server admins easily identify and block malicious users by monitoring and analyzing the behavior of your players. AntiCheat will look for tell-tale signs of hacked clients, as well as implement limits into the game so that players cannot gain an advantage by hacking.
CompatNoCheatPlus (cncp) provides compatibility between the anti cheat plugin NoCheatPlus and other plugins that add game mechanics different to the vanilla game behavior, such as mcMMO or plugins that add npcs such as Citizens. You need NoCheatPlus for this, NoCheatPlus can not be replaced by this.
CoreProtect is a fast, efficient, data logging and anti-griefing tool. Rollback and restore any amount of damage. Designed with large servers in mind, CoreProtect will record and manage data without impacting your server performance.
Grief Prevention Grief Prevention stops grief before it starts automatically without any effort from administrators, and with very little (self service) effort from players. Solve all your grief problems with a single download, no database, and no configuration step.
Steel Security I wanted to put and end to all of this, so I started the creation of Steel Security. My goal is to have one plugin that will make a server as safe as possible with minimal work for the admins that covers every last aspect of grief prevention.
Lockette The sign-based container and door lock for Bukkit!
LWC For chest protection
Survival Server
Buycraft For getting those essential donations to keep the server running
ChestShop For letting players trade
Towny For making towns and grief prevention <-- seems to be missing Please comment
Craftconomy is going hard like cold nipples. Defeat communism one linked server at a time!
Regios is here to pay up in sheer autistic customizations. Hoorah for LSPS!
Simple region market using worldedit and guard to make zone and sell them
Creative Server
PlotMe
Prison Server
PrisonMine - The successor of the now discontinued MineReset plugin.
PaidRanks - Good for ranking up players with a set price
Factions - Creates competition between players and allows you to protect your land and build an empire
VanishNoPacket - Find those noobish xrayers
TreeAssist - Auto-replant trees in a selected area
CombatTag - Kill players who PvP log

Are you talking about a plot world or a regular plot in a regular world?