On Phi Phi
See:
www.travelforum.org/thailand for tons of information on travelling in this area.
Also, The Lonely Planet Travel guides have great information on this area, but, EVERY traveller has it, so the accomodations listed in it are usually a little more crowded and a little more expensive than they should be. I carried two books on my first trip and had the best luck when I found something in the Rough Guide that suited me, and it wasn't in Lonely Planet.
There are three resorts on the north end of PP island. They are absolutely beautiful, but secluded... 20 minute longtail ride to town (Ton Sai Bay). They are priced around the same as the high end hotels (like the PP Princess) in town. I've stayed at the following places on Phi Phi:
PP Island Village (one of those three on the north end, supposedly the nicest). It was about $70 US a night for a beach front private bungalow. One of the nicest places I have ever stayed. Along the lines of the Rockefeller resorts in the Carribean or the "Top 10 Safari Camps" in Africa. That being said, the Gold Palm dive shop on Premises is more expensive than the dozens of shops in town... and twice as expensive for the most common dive trip: KingCruiser/Anenome/Shark Point.
PP Princess. (right next to the main peers). Overpriced when compared to PPIV, but a nice, small clean bungalows and a great location for Ton Sai Bay. The problem with that area of PP is I think it smells like sewage and has too many mossies.
Charlies. I thought this place was horrible, but many people, espcially the backpackers, swear by it. Cheapest bungalows on a very nice beach (crowded and very shallow for 100s of yards). If you want one right on the beach, email ahead. Good, cheap restaraunt.
And a nice, tiled bungalow right on the beach for $20US/night. It is down by the new Mosque, over the bridge (there is one main road/path on PP). It is out of town (but, you pass all the dive shops, so you'll always know who is diving where the following day... which, is kinda how you book diving on PP... last minute). About a 10 minute walk from the pier, very nice (but crowded like Charlies/Princess). I like this beach better than the one at Charlies, but, I'm in a very small minority.
If you make a left off the pier there is a hotel/bungalow complex that looked very nice. On a very nice beach. Looks secluded and private.
I've dove with White and Blue and PP Divers. Both have very good reputations. Moskito Diving has the best rep on the island, and a plush liveaboard for the Similans... and, they sometimes do two day trips to Hin Maeung/Hin Daueng... which I highly highly recommend.
The best restaurant on PP is a French place that has an open front. It is right near the beginning of the cobblestone path/road... the Blue something or other. Cheap, decent wine list (South African, French wines are way overpriced in Thailand, and they tend to have off year vintages).
I've never dove from Phuket (other than launching from Chalong to get to Similans), but I have stayed in Kata and Patong. Don't stay in Chalong, unless you are on a boat moored. Kata is nice (and I regret never having dived off of Coral Island, another place along the lines of PP Island Village). Patong is a specticle worth seeing. I regret havning wasted my time staying there (got in at 5pm, left at 10am and wished I had stayed to Karon or Kata and shot up there for diner). Phuket is just not my cup of tea. Most of the very serious divers head to PP... although cheaper liveaboards are available in Phuket (and they all leave from Chalong, not from PP... You take the ferry over).
BKK... tons of places. Koh San is a good starting place... espcially if you are heading into Viet Nam... You'll meet plenty of people who have just come from there... it is kind of the central hub of the SEAsia traveller. Personally, I prefer China Town on the river (River View Guest house, but, a LonelyPlanet special). Or, further down towards the Orient hotel there is a variety of accomodations and some very good deals. Any of these places are good to do the BKK touristy thing (although, have your suits made in Viet Nam, cheaper the town that is famous for it is just South of Daneng, a well liked travel stop for the American/European traveller). If you are comuting through BKK (arriving and departing) you might want to start on Koh San, and finish elsewhere.
The links listed in this thread are all very good sites, the one I listed was my personal favorite. Also, you can get up to the minute information on the Lonely Planet's Thorn Tree board.