While I haven't stayed at Monte Carlo, I have stayed and Luxor and found it OK. The problem with Luxor is that the inclinators are for specific floors, and you could have quite a trek to get to the inclinator for your floor.
I am a current fan of Bellagio (so I guess worse case you can always take the tram over quite easily). Have you checked on rates with AMEX? I got a great rate through the Platinum Travel Service of $139 per night that included breakfast.