Phnom Penh. If possible, this place is more hectic than Bangkok! Certainly, another place I get to use the word "cacophony".
One of my favorite things to do in a new city is to spend hours just walking around enjoying the sights and sounds. But, when the temperature is 85F and the humidity is 80%, that makes walking around a very sweaty affair!!
But, Angkor Wat...I will sweat as much as is necessary!
Definitely one of the great places to visit on the world. You will want to spend days here. Tickets are sold for 1, 3, or 7 days. You definitely will want and need more than 1 day. and, currently the difference between a 3 day and a 7 day pass is only $10 ($62 vs. $72).
Stay in Siem Reap, about 15 minutes south and take transportation into Angkor each day. There are so many places to stay and so many places to eat, you will find whatever you want and budget for.
There are a number of ways to see Angkor. The most popular seemed to be hiring a guide with either a van, or a tuk tuk, depending on budget and tolerance for heat. I also saw a few people traveling around on bikes. This is an option I considered, and am glad I rejected. The area it too large, and too hot for me to comfortably enjoy that way.
I chose to rent a scooter in Siem Reap, which was perfect for me. I could explore at my own pace, and get from temple to temple quite easily. Something to keep in mind, is though you will see the main temple (Angkor Wat), you will also want to see the dozens of other main sites in the area, and there will be miles in between stops at times.
Getting to and from Siem Reap
There are 2 main ways. The best is by plane, and there are direct flights from Bangkok and Phnom Penh. But, you can also take a bus between Siem Reap and Phnom Penh. However, I was warned against this option by many locals, sighting danger of the trip. Now, it is possible, that is the normal answer they give tourists, the flight to Phnom Penh was so affordable, I chose the plane anyway.
As long as I was in the country, I wanted to visit the capital.
What I found is a city that is not conducive to tourism. And, oddly expensive relative to SE Asia. Going to restaurants in Phnom Penh had me looking at prices that I would see in The States or Western Europe.
This is one of the places in the world where I can say it is okay to skip.