I love cats. I grew up with them. However, for some reason, I am now allergic to them (so is DH and DS2). I still love them, I just can't be around them. But they are easy pets as far as I'm concerned. I used to have one when I worked out of the house full-time (before kids) and I just left her all day without a worry. I did have her front claws removed, but Angie is right, if you are going to let a cat out of the house, don't de-claw. Mine used to be so scared to go outside.
Now we have a puppy/dog. SO much more work! Can't leave the house without putting him in his crate and we have to keep him in just a few rooms because right now he is very destructive.
Maybe take your son to a shelter to let him hold and play with one. Make sure he isn't allergic too! Good luck!