Convenient location
firm bed
good shower
individual room temperature control (even if that means a window that opens!) I cannot sleep if it is warm...
the fifth would be between a restaurant on premise or internet connection (most my travel is busiess!)

I always sleep with the curtains slightly open. It is a long story but I once feel asleep in my hotel room...woke up...looked at my watch on the nightstand and in a panic realized I was late. Quickly showered, dressed, made up and shot out o the room....to see total darkness. After a brief moment of thinking the world had ended I looked at my watch ---right side up -- and found it was 2:00 in the morning...not 7:30.....