The problem with the silkie is that they really don't lay at all. It would be strictly a pet, but it is a bantam, so it wouldn't eat as much as the other chickens. It also might have problems in the winter (either getting muddy or wet). It also wouldn't be as destructive when free ranging.
The problem with the buff orpington is that they lay, but they are known for going broody. They are also quite large (8 pounds). This means I would have a large bird that eats a lot that isn't laying all that much (3 eggs a week according to Henderson's guide). Based on looks, it is my favorite chicken.
Here are the current breeds I'm considering:
2. Australorp - the Australian version of the orpington. It is usually black and in my opinion not as pretty. But it lays 4 eggs a week and doesn't go broody. 6.5 pounds
3. Easter Egger - four eggs a week. 5.5 pounds. I really don't like how they look though.
4. Red Sex Linked (golden buff) - five eggs a week, but bred for production, so after two years they start having problems. 4 pounds
5. Buff Orpington - three eggs a week and goes broody. 8 lbs
I'm currently leaning towards the buff orpington, australorp and the golden buff.
Best case senario, I would be getting 9 eggs a week, enough for each of us to have one egg, plus three for baking. I might still have to supplement, seems like we go through about a dozen eggs a week, but the majority of eggs would be coming from our flock.