I stayed at the King guesthouse in Siem Reap. It wasn't fabulous, but it was only $6 a night and had all the amenities I needed.
The three-day pass is the best, I think. I really liked the atmosphere at the temples... tourists aside... and three days gives you lots of time to see everything and linger at some temples if you want.
My temple pictures are
Cambodia August 23-31, 2007 - a photoset on Flickr <-- there if anyone wants to see.