I agree with slick, adult cats from a shelter could be very affectionate too. Once I went and saw this cat i fell in love with. He was an adult, and once I walked over to him, he immediately got up from sleeping and started purring and rubbing himself against me as best as he could. The people said that if you hold him, he'll do whatever he can to stay on you as long as he can. I was soooo sad when my parents said we couldn't get him.
So go to a shelter, and look for a cat, and you'll know right away if its the right cat for you.