It sounds like you've let them walk on you and now they're used to it.
Tell them you will do one load of whites and one load of colrs per day. Period. If they don't have their clothes in the hamper when you do laundry, and they have to wear dirty clothes to school, tough. If they actually do wear dirty clothes to school a time or two, they'll figure out that you mean business.
Depending on their ages, you can make them responsible for their own laundry. My daughter got into the habit of bringing me all her dirty clothes on Sunday night, and I got fed up with it. She was 11 when I showed her how the washer and dryer worked, and told her that I was no longer doing her laundry. If she had no clean clothes for school I didn't want to hear about it.
She was a slob about picking up her room - I just closed the door, and told her that if I stepped on anything and broke it because it was on the floor, I was not replacing or repairing it. She didn't believe me until one day I accidentally stepped on a mix cd that her boyfriend had conmpiled and burned for her and shattered it.
I cook one dinner. Anyone that doesn't like what I cooked is free to go into the kitchen and fix something for themselves, as long as they clean up after themselves. If they don't know how to cook, they can make themselves a peanut butter sandwich.
I clean up the kitchen one time after dinner. Anyone that doesn't have their plates in the sink when I wash dishes will have to do their own.
I also have no problem with yanking privileges. If they can't help out a little, then they don't need to watch tv, play video games, talk on the phone, or use the computer.