10day Trip to Thailand.. Any suggestions on which cities to visit?

Just got back from a super trip to Thailand. We visited Bangkok and Phuket. If you're in to diving and snorkelling and a whole bunch of watersports like parasailing, jet skiing etc. then I suggest you stay towards Karron and Kata beaches in Phuket. Haven't been to Koh Samui so can't comment. Phuket was insanely fun. :) If you haven't booked, you might want to check makemytrip.com - we got kick *** deals for December compared to other places online. Expedia was expensive and so was travelocity. There are plenty of package tours in the market too if that's your scene.