How to best manage 1 iTunes account with SEVERAL devices in our family. We have 1 iTunes account for my family. We have 4 iPhones, 1 iPad, 2 MacBooks, 1 iMac, and several iPods.

I understand that each device can be configured to only sync certain playlists, so I do not have to listen to my husband's music, or kids' music, and vice versa.

What I do not understand is that when I try to sync my iPhone, I get 100 apps on my phone.  Is there a way to create playlists for apps and have only certain apps sync with certain devices?

Also, I have all of my business contacts, my work notes, etc. on my phone, which I do not want on my kids' phones.  Do I ultimately need another account?
If I need another account, can I still share everything that is already on the original account, or do I lose it? Thanks!
You can use a shared Apple ID for the iTunes, and app store purchases. Yes, you can select which apps sync to different devices


  To sync downloaded apps to iPod touch, iPhone, or iPad: Connect your
  iPod touch, iPhone, or iPad to your computer.
  
  In iTunes, select your device (below Devices), and then click the Apps
  button.
  
  Select Sync Apps, and then select the apps you want to sync.


You can create a unique Apple ID to use that for syncing contacts and calendars via iCloud. You can also sync contacts and calendars from an Exchange Server (or Google). Assuming you don't share your Mac account across the entire family, you can also just opt to sync contacts and calendars locally. 

You may find the Macworld article All about iCloud: Common signup scenarios to be useful.