The Sofitel El Gezirah is on its own island. The hotel was originally a Sheraton, but a few years ago, Sofitel took over management and brought in Pierre Yves Rochon to re-design the interiors. He did a really nice job and, although this is not a Four Seasons, it is a very acceptable place to stay.
Kebabgy is an iconic restaurant that serves probably the best Egyptian food in Cairo - the bread straight from a wood fired oven in the restaurant. Le Deck juts out into the Nile and is really special for Cairo.
I have stayed at all the so-called five stars in Cairo and I prefer FS Nile Plaza because of its proximity to the Cairo Museum and its on-the-Nile position, but I still like the Sofitel if your budget is a little less - it's a really surprising hotel.
I also like FS First Residence but can't stand the heavy chlorine in the water. No idea why it's like this.