I've been to Luxor twice and love it. It is safe but there isn't a great deal to do outside of the hotels, a few restaurants, a couple of pubs and mainly jewellers shops.
The pyramids are on the outskirts of Cairo, about 400 miles away! You can get there, last time I went some of our group went on a trip organised by our travel company. It cost nearly �200, they were picked up at 4:00am, flew to Cairo and got back about 10:00pm the same day.
I also saw a poster offering a trip to the pyramids via train, it was half the price but took 2 days.