Went to Luxor about 6 years ago, loved the place.
Couple of points:
It's a Muslim country so do remember to abide by their rules, they are an incredibly friendly bunch of people, but just remember a few simple rules and you'll be fine.
Don't be put off with haggling over prices; it's part of the norm over there when buying merchandise off the street (but don't go into a Cafe and haggle over a coffee, that's fixed!!

)
Luxor itself has a handful of historic things around it, a good trip is into the Valley of the Kings itself which is a short journey by bus.
There's options such as camel riding (and racing if you get a good guide, camel racing is a brilliant experience) as well as 4x4's and surfing in the sand dunes.
I found the place to be quite cheap, but do also remember that the locals will offer to help out on almost anything and then say "Baksheash" (sic) which is tip, if I remember rightly Islam is quite charity based and so a 'tip' is often the norm for even a smile or a point in the right direction.
Can't really think of any faults in the place. I certainly wouldn't stop there much longer than 3 or 4 days, maybe 2-3 days to see historical sites and a day on the dunes, but it's certainly a nice break.
Few things I'll never forget is just walking down the back streets of Luxor and talking with my partner and a few locals shouting "Emmerdale Farm, eeee by eck" as they pick up any accent you have within an instant. Also remember going doing a back street and seeing a bloke with nothing below the waste (sorry just read this back, I actually mean had no legs and was using his hands to walk - my bad) just walking down the street while snake charmers amused themselves and the locals played games in the street with 'markers' made from dried camel dung. Definately a few magical moments.