I was there two years ago for Spring Break. My roommate's dad owns a bunch of clothing stores down there so we stayed in his apartment for most of the time. Stores are called "19.95", "19 World", and some of the newer ones "Jeans.com". Mostly clothes for younger folks.
We saw about everyplace on the island.. San Juan, Ponce, Mayaguez, Arecibo. Took a boat out on the eastern side of the island near that 5 star hotel that's kinda built into a cliff... Beautiful island. Lack of open container laws is cool.