Turn off iCloud, delete the address books on the Macs and iDevices (except for the master list). Turn iCloud back on.
That is a guess, and an extreme measure, but it would work.
Whoa. No need to delete anything. I used MobileMe for years and upgraded to iCloud. During the process, I created a "temp" iCloud account just for testing. When I "logged out" of the temp account on my Mac, all my contacts were deleted, despite the fact they weren't created with that iCloud account. I was in a chat with Apple tech support and they talked me through making sure at least one device had good data. My iphone had good data as did my iPad. I enabled iCloud on each of them and nothing got duplicated. I expect that if the contacts on my Mac had not been deleted by my "temp" iCloud account, I still would not have any duplicates.
When it asks if you want to keep or delete, make sure that on at least one device you say keep!
I think Apple expects people to use user accounts with different iCloud accounts.
That is probably the best way to go to ensure that your stuff remains separate.
As for contacts, in Settings->Mail, Contacts, Calendars you can add a secondary iCloud account and have it only sync contacts.
So what you can do is setup a "family" iCloud account where you put your family contacts that sync across you, your kids, and your wife iDevices and then sync the rest to your personal account.
You could use your iTunes account if you have a separate one for purchasing and iCloud.
Family account for iTunes/shared stuff and personal accounts for personal stuff.
I think Apple expects people to use user accounts with different iCloud accounts.
That is probably the best way to go to ensure that your stuff remains separate.
As for contacts, in Settings->Mail, Contacts, Calendars you can add a secondary iCloud account and have it only sync contacts.
So what you can do is setup a "family" iCloud account where you put your family contacts that sync across you, your kids, and your wife iDevices and then sync the rest to your personal account.
You could use your iTunes account if you have a separate one for purchasing and iCloud.
Family account for iTunes/shared stuff and personal accounts for personal stuff.
Holy cow. I did not know you could set up more than one iCloud account per iDevice. That could get confusing!
MotionMan
Hold on. I don't think Apple supports multiple iCloud logins. They do support a separate Apple ID in iTunes. So your iCloud login can be one thing and your iTunes login can be another. But that's it. And there is only (supposed to be) one iTunes login per iThing.
The only way to "log in" to a new iCloud id is to "log out" of the current one which wipes everything. Well actually it asks you if you want to delete everything. If you answer no, you stay logged in. It won't let you log out until you answer yes and then it's too late. Your contacts/calendar/whateveriCloudrelated stuff is gone unless you log in that iCloud id again.