I would like to hire a driver for touring Angkor who speaks good English, has a car with A/C, and drives safely. Does anybody have any recommendations? I saw that a few people in the post hired a driver only (and no guide) but I could not find any contact information for them.

generally drivers do not have good english or guide skills....

Wait until you get to Siem Reap. I hired a driver whose English skills were "good enough" for my purposes. His van had A/C and he drove safely. I did so simply by using the driver the hotel sent for me at the airport. If he had not been appropraute for my needs, I simply would have asked the hotel for a different driver. By the way, the drivers I observed at Angkor were all pretty good. I didn't see any of the "wild" driving you sometimes see elsewhere in Asia (Bali comes to mind...) The drivers are not guides, but they know the temples. I was able to give my driver instructions such as drop us off at the East entrance and pick us up at the west entrance. He also knew the routes of the big tour buses so we were mostly able to miss the huge groups. I hear that most drivers are able to do these things.

Do yourself a favor and hire a guide with a driver. The expense is minimal. The guide can give the driver all instructions--and with Angkor Wat and the surrounding temples/ruins, although I don't usually use guides (preferring to do things on my own), I am very happy that we did use one on our recent visit. We had an incredible experience, heightened by the knowledge of our guide.

I will hire a guide then. I saw many recommendations on this post. Thank you for your suggestions!