I went to Sharm last February - it's GORGEOUS. You have to try scuba diving while you're there, it's unbelievable. The nightlife is alright, but limited to the casino areas and in hotels. It's also pretty good for shopping - I bought 3 pashminas (really nice quality ones!) for the equivalent of £10 in total. Just be prepared though to have your bum pinched everytime a man walks past and to have people offering to give you things for free if you kiss them. In other words, handcuff your boyfriend to your side! It should be really hot too in September.
One thing though - I'd advise covering up a bit in markets or anywhere away from main tourist regions - not only will they regard you as a complete slut (even if you're just showing bare shoulders or thighs), but I once got whacked on the back of the legs by a old man because I was wearing shorts and 'displaying too much flesh'.