By far Attack of the B-Team is the best modpack I've ever played, but it feels like there's something missing. I realized that it needed some more adventure elements. Then I remembered my favorite mod; Aether II. If you have not heard of it, it is the revived and redone version of the Aether mod. Its a great mod by itself but I think it would go wonderfully with B-Team. The clouds would be an extremely quick and cheap alternative to pipes, and continuum ore is always fun to mess with. not to mention all the new trees and decorative blocks it adds. Best of all there are rainbow strawberries. If the mod isn't awesome enough as it is there is a new 1.7.2 update coming out soon with 140 new blocks, 80 new items, 10 new biomes, and massive dungeons full of Valkyries. The moa breeding system will be greatly improved making it possible for billions of moa variations. I would be content to install it on single player, but with me rarely ever playing SSP it would be of little use to me. Plus the mod is meant for multiplayer and contains a few useful multiplayer functions like parties. The mods addition to B-Team would also help the development greatly by spreading it to a wider audience, speeding up the speed of donations which are rewarded by a few in game perks as well, such as custom moa skins and a glowing player model.
Personally I believe this mod is the one thing we need to change B-Team from an amazing modpack to an absolutely jaw-dropping one.
http://www.minecraftforum.net/topic/1842350-162-alpha-aether-ii-genesis-of-the-void-fixed-launcher-improved-performance/
http://aether.wikia.com/wiki/The_Aether_Wiki:_Genesis_of_the_Void