I'm surprised no one's suggested these mods yet but here's what I'm thinking Mekanism, backpacks,portable tanks, tinkers construct.
the reason I suggest mekanism is the universal cables since we don't want to carry around a bunch of different cables and what not. The energy cubes are nice and you can wrench them and hold their charge and are upgradeable even when they have a charge. Also the early power generation would be a nice addition.
Tinkers construct because repairable tools would also be a nice addition and we wouldn't have to make and carry a bunch of tools around. also with the addition of back packs the tinker knapsack would be nice to hold extra bags and what not out of our inventory. The backpack mod also has a crafting table bag and you can also add a book to it so it can store some basic recipe's.
last but not least portable tanks since we don't always want to carry a bunch of buckets with us fill a tank wrench it and wander around.