Greatbows (DS II)
Greatbows are usually good items to use to snipe enemies off of higher areas. While the Bow is faster, it doesn't have the power behind it like a GB. You won't be getting one for awhile unfortunately, since the Alonne Greatbow isn't available until the Iron Keep.
Greatbows are usually used with troll sets when PvP comes to mind. They are not nearly as fast as a regular bow and you would be better off using a Avelyn instead. However, the one redeeming quality of a GB is that with the right timing, you can knock an opponent off ledge if you are invading them.
Here are the all of the available Greatbows found in Dark Souls II.