-First and foremost, you need permissions. BPermission is the old go to. Works like a charm.
-Next, Essentials is great for doing a wide range of things like selling items and lots of standard server comands as well as an in-game economy.
-SWS Watchdog is great for rolling back any grief. It's a little bit unintuitive at first, but it works well.
- If you want players to be able to do their own land protections (as well as protect your spawn area) Residences is absolutely wonderful (and ties seamlessly into the essentials economy).
- HeroChat is great for managing chat classes and such.
- If you want chest protection I recommend either Lockette or LWC. Both are great.
And those cover pretty much the main plugins.
Other neat ones you might want to add are:
-Spectate: For viewing a player's action... make sure they aren't doing anything against server rules
-Mob Arena: Allows you to create awesome PvE wave arenas. Complete with bosses and other goodies
-Lift: is neat for cool little elevators
-WorldEdit: great for server staff doing large builds.
-Multiverse: managing multiple worlds
The best thing to do is to get all the most important plugins working as well as permissions. Then the other fun plugins can be worked in.