I would rather have small headphones of some kind that the 2DS can actually power well enough.
Emphasis on cheap. I know, I know, at that kind of price it's just junk...but I want the best junk for my money. ;)
Let's say nothing above $35
Check out SoundMagic E10 or possibly Phillips SHE3580 for IEMs
I'll give you a review for E10: http://www.head-fi.org/t/581119/review-soundmagic-e10
if you want actual headphones then JVC Flats are rather popular.