I'd recommend going to Phi Phi Island from Phuket for atleast a week of that time. Don't bother sorting out accommodation though, when you get off the ferry there is places that can sort your accommodation to what you are willing to pay.
Bangla rd is the most popular place to go drinking @ Patong beach with about 300 bars in one street. almost 10 years ago
Depending on what you want to do in the Phuket region there are plenty of things you can try out... cooking classes, scuba diving around the island (Krabi is better from what i hear though..) day trips to Phi Phi and Krabi, we stayd in Patong for a couple of days and it was great for fun activities as well as working the elbow muscles with a beer or two at the bars and clubs.
there's go karting, a shooting range, fishing charters, some okay surfing spots, paragliding...plenty to do!
One of the better bars we went to was the tiger bar in Patong... almost 10 years ago