and the few times you want the reach of the 70-300 you will be glad its there just keep it in the bag until you need it then its not grabbing much attention.
I taped mine w/ black tape, looks way cheaper now and less white, you might want to do the same - and it protects the white paint from scratches as an added bonus.
It's just as it been said before - usually you'll want an ultrawide (standing inside a temple or close in front of a pyramid :-), tight-spaced local markets) and a tele for far-in-between shots. I'd say the 17-40 + 70-300 + the 50/1.4 for very low light indoor shots. Then you can just choose one zoom according to the occasion and mostly stick to it, you don't want to switch lenses in dusty or crowded places. And bring a sensor cleaning kit! And a mini travel-tripod.
We are planning a 3 weeks trip to Egypt + Jordan (other than usual highlights like pyramids, luxor, petra etc... I am hoping for few days in desert too. both in egypt and in jordan).
If you're going not now but next summer you might think about giving your wife a Rebel instead of a p&s so you can share lenses and - most important - you have an eos backup if one fails. This happened to me in the middle of my Egypt trip in Assuan, it's just been too hot, the camera couldn't take it - very frustrating experience.
I would probably take the 85 for some candid portraits of the locals with some nice bokeh!
And remember to have enough $$$ around for baksish, the locals won't understand if someone with a big camera isn't giving away lots of tips, that's the tradition and the local social security system! Personally, I found taking portraits extremely annoying, so I preferred sticking to columns and temples that don't bug you to buy a talisman.