Yes, yes. All of my thoughts in an entire post!If only 1 mod, it would have to be thaumcraft. Most of the others don't matter a whole lot when you are talking about just them and vanilla mechanics. Thaumcraft has a complete system of items that can stand on its own without interaction from other mods.
Don't get me wrong, there are a lot of great mods in the mix, but by itself, only Thaumcraft stands completely by itself. And it isn't even complete yet.
Edit: Looking through the posts, I saw stuff about BTW, and something occurred to me. BTW will be compatible with all mods when the Official Minecraft Mod API comes out. Forge will be obsolete, unless of course the API sucks hard.