I don't have a lot of cards, hence not a lot of doubles. It is probably a good thing that our local store sold out quickly as I would be tempted to spend money that I don't have. I intend to trade my couple of doubles with a RL friend that I will see around Christmas.
If I had more doubles and was doing some trading, I would probably trade for a couple of special villagers. Lionel was my favorite character in my main AC:NL town. I lost him (and the entire town) when the cartridge popped out of the DS while I was out doing errands. I know he will show up in HHD anyway, but I would invite him to other villagers homes because he always made me smile.
If I had the whole first series, I would probably save to trade for series two. Maybe I would use some to trade for a card with 7-11 DLC on it. I adore that series and would love the items with the 7-11 logo on them that are not included in the North American DLC.
Hopefully, I can get at least one more pack or two of series one.
I am wondering about trading some that I do not have doubles of for a couple of special villagers (like Lionel).