Boone + Cowboy Repeater = Carnage
Seriously, give Boone an accurate, powerful, high RoF weapon and he will dominate almost everything. My only problem is finding enough ammo for him

Also, does anyone know if weapon mods work for weapons you give to your companions? I noticed they don't show up visually, but I'm not sure if the effects are there or not.
Edit: If you tell Boone to leave when you have the Lucky 38 suite, He basically says "Whatever you say, boss." and goes there. I don't know where he goes if you tell him to go elsewhere or you don't have the suite, I assume Novac.