Can't go wrong with the Red Canal in Mandalay. We stayed there in the first week of August and would stay there again. You should contact a local travel agency to book any hotel as they will have cheaper rates than what you can find on the internet or contacting the hotel directly (sometimes $15-20 cheaper per night than "discounted" rates available to foreigners).
In Bagan, I would highly recommend the Tharabar Gate. I didn't see any other place in Bagan that looked half as nice. And it's a nice location with easy walking and biking to many of the best temples and pagodas.