The Mercantile is great for gifts and great for self-gifts. Personally, I was all about the self-gifting when I was in here, but I also managed to pick up one thing for someone else.
The place is essential for any sort of foodie. They've got a great selection of food accessories and things to make your cooking life easier. The meat rubs that Kim mentioned are actually amazing -- they've got little sampler containers for you to smell exactly what Caribbean spices are going to be like on your chicken, among a gazillion other kinds.
They have cute gift ideas like different sets for a "do-it-yourself" night -- like if you feel like making sushi or Indian, the owner has put together a little set with everything you need for the night. GREAT idea.
Also if you're a health-conscious person or if you have a gluten allergy, there is a huge selection of gluten-free products including chips and crackers! There is hope for people whose bodies reject gluten, and the Mercantile can help you stay on track.
Stuff does go on sale too, so it's worth stopping in for a gander every once in a while!