Do you to have fun, be useful in a group, or make money.
I'd say engineering for fun.
Enchanting would be useful for a mage in a group to disenchant items.
I think the only thing you would lose on is Blacksmithing. BS is more a labour of love then anything else, or just a labour.
The best way is to ask your guildies what they like about their craft and see which appeals to you.