I don't think you need a guide once you get to the Valley of the Kings, but having a tour (or private driver/guide) to get there from your hotel in Luxor and to give you some background info would be a good idea.
For the temples in Luxor (Karnak and Luxor), a guide might be beneficial depending on how much you want to understand beyond just experiencing them. I'm not sure what other temples you will be visiting, or how you are getting from place to place, but you will be seeing a lot of symbolic painting and hieroglyphics, and if you want to make sense of it all, a guide will definitely be worthwhile. Assuming Abu Simbel is toward the end of your trip, by the time you get there, you should have gotten a good feel for recognizing certain images.
Of course, you can just admire all the artistry and enjoy everything that way too.