Infinity
Minecraft PC IP: play.cubecraft.net
CubeCraft Games
SpringWarz
Gainfullterror
Infinity all the way; Bows can always be recreated without too much to spend, while arrows would constantly be a worry without it.
SanCookie
Yeah would probably go with infinity too, because mending is also way harder to get, while you can easily get infinity from enchanting
SpringWarz
It's a treasure enchantment. Add it to a armour/tool and while you are holding whatever item has the enchantment, every time you pick up xp, you will repair the tool/Armour you are holding