Siem Reap/Angkor Vat

Ask for a tuk-tuk at the hotel, you are likely to get a nice guy who knows the routes and routines well. We paid $15/day for normal days, which included cold bottled water in an icebox. Out of the 3 temple days 2 were normal ones, one longer one to a few outlying temples and one more day to Tonle Sap lake. Those longer days were $30 each.

Our route was the so called big circuit on the first day (thorough Angkot Thom to Prah Khan then clockwise to Ta Prohm), second day was Angkor Thom mostly + the sunset view of Angkor Wat from the nearby hilltop temple (very crowded). Third day was sunrise at Angko Wat and the temple itself, after that Roulos group of temples outside the city . The total number of temples visited was 20. Buy the excellent guide book from the hawkers for $10 or so. Fourth day we spent on Tonle Sap at Kampong Phluk, private boat for the day cost $30 or so, after a 45 minute tuk-tuk ride from town.

Besides Angkor Wat (note spelling, it's a wat, a temple, not a vat), there is the Land Mine Museum, the butterfly museum, and the war museum.

One of the best things to do in Siem Reap, and any town in Cambodia for that matter, is to hire a tuk-tuk for a day and go out into the countryside. You will pass by houses, small villages, people working in the rice fields, ox carts, children waving and saying hello etc. You can stop and take photo's whenever you like and of course say hello to local people yourself! Cambodian people are extremely friendly and they are just as curious about you as you are of them.
People come to Cambodia to see Angkor Wat, but it is the local people that will really leave the lasting impression on you.

With three days I would recommend either the following:

Day 1- Small Loop
Day 2- Go farther afield to Kbal Spean, Bante Srei and Bante Samre
Day 3 - Big Loop & Roulous temples

You can organise tuk tuks through hotels or just on the street. Some are better than others, though if booked througha hotel the drivers are often pretty good guides - they give basic information about the temples etc, but usually leave you to explore the temples yourself. Not sure about having a guide actually take you through the temples, you'd have to look into that.

Also, I think that the two day pass is the same as the three, so don't feel you have to use all three days in there. The first time I went to Angkor (twice now), I did a day farther afied at Beng Melea (great temple, not included in the Angkor pass) and then Kompong Phluk (great village on stilts). But that's just me - I'm not cut out for three consecutive days just visiting temples!

Cheers