It's easy to visit Angkor Wat under your own steam. Buy a flight to Siem Reap and choose a hotel near the ruins. I would organise a guide and driver for the first day. Use this time to drive through the core site and on to some of the outlying temple complexes. Then, if you are a fairly confident rider, rent bicycles to explore the Angkor Wat and Angkor Thom complexes. There are quiet lanes for cyclists and the whole experience is far more atmospheric. Try to visit the Angkor Wat at lunchtime, when most visitors return to their hotels for lunch. The best guide is Dawn Rooney's Angkor, published by Odyssey Books but laser-printed in Cambodia, where it should cost only a few dollars from a small boy.
For a sundowner drink, visit the former Foreign Correspondents' Club, a beautiful art deco house that also has bedrooms (www.fcccambodia.com).
Try to time your visit to include a Saturday night. A Swiss doctor puts on a fund-raising cello concert and talks about his work in Cambodia. It is a thought-provoking experience.
Wifey has done her research and is primed and ready. :o)
She has already sussed out the site passes we need (1 day, 3 day and 7 day), we've booked our accommodation and she is fully aware of the good doctor and his cello concertos. He puts them on to fund his children's hospital.
This is clearly a great cause, but I can't abide string quartets and the associated music so I will leave the ladies to it on that night. However, the landmine museum will be worth a visit, so there is plenty to see and do for us all.