I run three spigot servers, a "main" one and two smaller ones bound together with bungeecord, a Tekkit+ server (with my own modpack - I have tekkit for 1.6.4 plus ICBM, railcraft, magical crops and a few other mods), and a Pixelmon server.
The spigot servers have ~50 plugins, including all the usual ones... essentials (including group manager), prism, worldedit, worldguard, dynmap, factions, towny, multiworld, voxelsniper, etc. The Tekkit and Pixelmon server have a subset of plugins that are relevant for them.
A lot to maintain quite frankly...
I am really proud of the Tekkit server, largely because I have built, with some help from my kids, a full blown implementation of a fusion reactor complex, oil refinery, emergency power setup, particle accelerator complex, and complete fluid storage facility, along with a complete implementation of Applied Energistics, including autocrafting of just about everything. This requires a lot of ME interfacing with Thermal Expansion, Railcraft, and Minefactory Reloaded for crafting things that can't be crafted in the Molecular Assembler Chambers.