I fell in love with Penzey's in Columbus and was pleased to find the Pittsburgh location is well-stocked, fairly large, and has very friendly employees.
Penzey's is a national spice company with 40 stores and an excellent website. Every spice you could possibly want is here, reasonably priced, and available in a variety of sizes. I started going here to get spices for Indian dishes and just keep coming back. They make their own spice blends, and a number of them are salt-free for anyone who is concerned about their blood pressure. They have all their spices in little jars so you can smell them before buying, and as a result the whole store smells delicious. They also sell a lot of different gift boxes - a perfect wedding or housewarming gift for a foodie friend.
Today we got a huge jar of their hot chocolate mix, whole black peppercorns, a big bag of bay leaves, turmeric, cumin seeds, and coriander - total $20.26. A lot of their spices come in bags so you can just refill the jars you already have - and their jars are very sturdy.
If you like cooking or baking, definitely get yourself to Penzey's.