Just thought I'd ask the members of the community which mods they consider as being well balanced around the original game? As in, what mods do you feel good things for the game without ever reaching a point where Minecraft's best items are completely invalidated? This can be technological, magical, monster mods, dungeons, or anything else. Just list them, and if they need configuration tweaks to make them so balanced, say so.
For those who don't mind a bit of reading, I've been writing mod examinations on Hubpages under the name Cliffwalker. So far I've done full articles for several mods, including the likes of Witchery,Enviromine,andLycanite's Mobs, and I have also written a few multi-mod articles to help those who wish to find upgrades for a specific aspect of their game, such as the Nether.