Best Minecraft Multiplayer Bukkit Plugins/Forge Mods (I know it's not steam... but still)

Bump

Mystcraft is pretty fun. It integrates well with other mods, too.

I have a pack of 53 mods that I installed from Youtubers that played them, but is for version 1.6.4, single player and multiplayer worked to me, if your computer can handle it, if not you can try to disable or put to minimum all CPU intensive chunk options like fast math, chunk update, etc.

But if you want to install by yourself, one of most useful are World Edit plugin, Not Enough Items(NEI), Optifine, also depending on the mods you like to, I would install MO' CREATURES, Backpacks, Tropicraft, Twilight Forest, Buildcraft, IndustrialCraft, Rei's Minimap, GLSL Shaders(Seus v10+ shaderpack) if you computer can handle them, Thaumcraft, Grimoire of Gaia 2, some Tornado mods(they are called Seasons or Weather idk, one of them, they are cool when a tornado appears at your house :D), some mods for The Nether, same for End, etc

Bukkit Essentials

This may seem like a stupid question but I honestly don't know- do my friends also need to download the mods, or will the automatically be added to their computers upon joining my server?

Hamachi

Non-modded MC on bukkit server.
Never gets old.

It takes less effort to open a port in your router than installing hamachi..