Are there any unique bows whose enchantments make them a better choice than a custom enchanted bow? [duplicate]
Solution 1:
Not really, especially if you intend to use the Smithing>Enchanting>Smithing exploit to make an incredible weapon, but the Nightingale Bow does come relatively close. If you're lacking in enchanting or smithing skill, this is a valid option to replace leveling these skills just for that reason.
http://elderscrolls.wikia.com/wiki/Nightingale_Bow