Which are some of the best mods for Minecraft?

I bought the game along with my friends last Friday and we are now playing together. We want to had a couple of mods to the game. We added one where you only need to chop one cube of the tree to make everything fall off. Is there some utility mods like this one that would improve our time playing the game?!

We can only play 2 or 3 hours a day because of work and whatnot. So I was thinking maybe getting some mods would make it even more fun but I have like no idea where to start since I’m obviously new to Minecraft.