Tricky one this, since one only really gets to see the famous from a distance so it's all looks really... My choices might all turn out to be bitches. I presume you don't have to stay the whole night, week month with them??
One night: Oh, any Bond girl, maybe two of 'em... (the ones that aren't bitches...)
One week: Sandra Bullock, cos she looks a bit like the most beautiful woman in the world
One month: Have to go back in time a bit here, Audrey Hepburn from the Breakfast at Tiffany's era: Cos she's the second most beautiful woman I've ever seen.