Most plugins added really depend on what *you* find fun. For example, in my server, I find McMMO to be a fun experience for my players and I. The main concept I'd recommend you follow is, if you have an idea, get someone to create that idea. It's what will make your server unique, not like any other cut-and-paste server.
But, for convenience, here's a few easy plugins for your server
- Permissions Manager (LP or Pex are the two best, arguably)
- Essentials
- Vault (Needed for economy)
- Mcmmo
- Jobs Reborn
- HolographicDisplays (For that advertising goodness)
- Worledit & Worldguard (Want to protect your spawn, right?)
If you want more, I'd recommend you check out my own server, and I'll be able to help you get started