Amanda, I'd advise you to go for a big 'un with that many mouths to feed because as your children get older thier appetites are going to increase and once your boys hit thier teens they're probably going to have massive appetites. Since slow cookers have no moving parts they last for years so it's best to lok ahead when you buy one. I've got the russell hobbs 6l and I can cook a good size lamb leg on the bone in it. It can cook enough for 6 people easily and have some leftovers too.

Russell Hobbs has a 6l that has 2 pots (a 2l and a 4l) so you can cook 2 dishes at once. I'm trying to figure out if I can just get the pot to go in my existing 6l with one pot - it would be sooo handy.