One Apple ID or Two? Can someone please help me out? I currently own an iPhone and an iPad and my son has a iPod touch 4th Generation. iCloud works well between them, but my wife is looking to get an iPhone as well. If she uses a new Apple ID can she still use my purchased apps? Or if we use the same Apple ID can you separate contacts or would turn it off on one device?
You should have one AppleID per person that you use for iCloud, Notes, Contacts, Mail, Calendar and to-do's. You then pick one of these ID's to buy things in iTunes and the App store. You probably want to use the ID you have used to purchased music and apps with up until now.

So setup your wife's iDevice(s) with her new AppleID. When you are done, go into Settings/Store and change the AppleID you to your existing ID (only in the store).

Now you each have your own iCould but everything you buy can be shared between the both of you.