Run by the same folks as Foursided (proprietor and artist Todd Mack), Twosided is a great little spot to go for custom cards and an array of unique gift ideas, both modern and antique.
Calling the shop a "delightfully cluttered establishment," Twosided knows itself well. Focus on the delightful, though, and not the clutter, because there's some endearing objects to sift through at this shop.
Make sure to look on all walls, the floor, window sills, and anything hanging from the ceiling, as the full-on displays offer some interesting stuff for sale.
Reader reviews, anyone?