Diana is a bit off the city center. But it is close enough to shop. Main merchandise in the building is clothing. There is a Diana Department Store and there are a few small shops inside. There is a cineplex in the building. There are a few restaurants such as Pizza and Swenson's Ice-cream.
What to buy: Fashion for men and women
Another one of Hat Yai's large department stores that contains various shops and eateries. It isn't within walking distance of central Hat Yai so you'll need to use some form of transport to get there. Sawngthaew is the cheapest if you can find one. These are the pick-up trucks with 2 rows of seats in the back. They cost 5 Baht. A motorcycle taxi costs 20 Baht. Tuk-Tuks are more expensive but if there are a few of you the cost can be shared.
When I was there ... there was a fashion show on sports wear and swimwear. There was also a contest for people to participate . Too bad it was in Thai and i don't understand what they say. The prize ... a swimsuit.
What to buy: Clothes, toiletories and souvenir items were really cheap here.