Agreed with most of the above. I'd go for two. A single cat will be ok as long as it is receiving enough attention and care. However, they tend to be a bit social amongst their own kind and eventually grow to play together, groom each other and even sleep together. If you aren't going to be able to give just one a whole lot of time, then a brother or sister would be an awesome playmate to help them get the attention and playtime they need. I have three siblings, 1 boy and 2 girls, and all three of them are full grown now. They still play with each other like they're kittens.