Not much to choose between Luxor,MGM,Excalibar and NYNY, they are all interlinked by a high walkway, have stayed in all 4, the Luxor had been refurbished by the time we went in April 06 and we liked it, and it wasnt over the top price wise after all you wont spend much time in there, too much to see & do.
If you stay in the MGM you are nearest to the monorail as it runs from the back of the hotel.
We once stayed in Circus Circus and it was the pits, never again.
My other piece of advice is take a direct flight.
Dont forget to ask at the desk when you check in for a free copy of Whats On, then you can plan your day.
Have a great time, its like Disney for grown ups.