if you and your partner are both going to be out for a large portion of the day then it might be worth getting two cats so they can keep themselves company during the day when no-one is home, a lot of the rescue sites I look at have pairs who need to be homed together, or cats who are familiar with each other and would prefer to stay together in their new home. I suppose it also depends on if the cat/s will have outdoor access, as if they're kept indoors all the time they will probably get bored faster and will need a lot more stimulation in their environment and a lot of interaction when you are at home. Otherwise I don't see too much of a problem, there will always be cats that don't mind being left by themselves for a while and don't need constant attention, it's just about matching the cat to your living situation which is important.
Some rescues will tell you that you can't adopt from them if you will both be working full time, it all depends where you go. In my experience the large rescues will have set rules about things like this whereas small independant rescues will be more likely to consider each case on it's own merits.
hope this helps a bit!
