I love Pop. They've got stuff I've never heard of and wouldn't try on a dare, but just the fact they *do* have it is awesome. They're the only place in the western 75% of the US to stock Captain Eli soda (pro-tip: try the blueberry, it's AMAZING), and the cute cashier chick agrees that Eli is some of the best soda to be found. The staff knows their products and can answer the most obscure questions imaginable. They can also order anything they don't currently have in stock.
It's probably good that Pop is so far out in the East Valley, because I'd be in there every day if it was closer to me.