I've been to both Phi Phi Island and Patong Beach twice.
Holiday Inn Patong Beach is regarded as the best hotel in Patong and one of the top ten in Phuket. We've stayed at the Burasari Resort which is next to the HI in the southern and quite part of Patong. Had lunch at the HI once and it was very nice property. If you want to party, the HI is walking distance to Bangla Rd. but the HI far away enough to get some peace, rest, and sleep day or night.
In addition to being a good base to explore Phuket and the rest of Southern Thailand, Patong is a playground. There are many things to do: shopping, dining, swimming, para-sailing, speed-boating, "banana-boating"

, or you can just sit and vegetate at the beach or in the sun at the HI pool.
http://www.flickr.com/photos/kalboz/page8/
Don't be afraid to go to Bangla Rd. It's just another street but with lots of bars and clubs. Go at least once just to check it out:
http://www.flickr.com/photos/kalboz/5397082448/
http://www.flickr.com/photos/kalboz/5396485863/
Phi Phi Island while it is stunning, IMO is also isolated and boring after a while. It is good for a day excursion by express boat as we did. For about THB 1,200 per person, you get RT transportation from/to your hotel, ferry express boat to Phi Phi, stops along the way to snorkel with colorful fish at Maya Bay (where "The Beach" was filmed in 1999), kayaking, snorkeling again, and feeding the monkeys at Ao Ling (Monkey Bay), lunch and tour at Phi Phi Don where you can relax until around 4 PM when it's time to sail back to Phuket. This full day tour (7 am - 7 pm) is highly recommended and lots of fun.
http://www.flickr.com/photos/kalboz/page6/
http://www.phuket-travel.com/destina...pp_express.htm