Don't get a boy cat, there is always the possibility that they could grow into being a problem territorial sprayer. There are also aggression problems in males that you don't tend to encounter in females (ie picking fights with other cats).

I have a little female tortoiseshelle domestic short hair, got her at the RSPCA 15 years ago and have never regretted it. Such a lovely little companion, likes to follow me around and sit with me when I'm reading, studying etc. But be prepared for hair, best defence is a good vaccuum cleaner.