I've been reading the dog thread and it's put a real smile on my face, what is it your cats do that warm your heart?
DCat1 will sleep across my feet when it's cold and keeps the warm in the cold months. He runs upstairs even we put the lights off to go to bed and makes sure he is there ready for me to get into bed.
He also meows at any household visitors and leads them to where his food is kept to tell them his starving he is.
DCat2 will stand next to the sink and meow at us when she wants a drink so we turn the tap on. She also choose the most uncomfortable places in the house to sleep at night despite having beds/sofas etc
DCat3 never leaves our side, she always wants to be on your lap or next to you. She will snuggle up next to you and do a contented little sigh as she drifts off to sleep, melts my heart.