I found a modded SMP called Mech Rehabilitated and it feels like a small friendly place that stays active. It is the kind of server you can hop on after work or classes and just relax or go totally wild.
The modpack has over 300 mods so there is a lot to do. People can explore and loot huge structures then go fight bosses and chase big power. If you are more of a farmer type there are lots of recipes and cooking stuff too.
Some of the mods mentioned are Create Alexs Mobs and Caves Terramity Farmers Delight with lots of addons Cataclysm Etched and Littlepictureframes for community movie nights.
The server just came back with a brand new version of the modpack and a clean slate. You have to fill out a short form to get reviewed and whitelisted before you can join.
