Yes you can do that but the email address you pick as your phones live ID will work with the Marketplace and will need to be the same email you use on your XBOX. (if you have one) This live ID will be associated with your Gamer Tag. The email address you use as your live ID will be the one you log in with when you first turn in the phone. This email address cannot be changed so you will want it to be your primary email. Skydrive will be associated with this email address as well but you can use the Skydrive app to log in to a different Skydrive box if needed. On apps that require login like Skype you can log in with any email address you chose.
I was afraid of that answer.
The problem is that i have created a Zune Live ID with my main email but with the wrong country.
This means that i cant put a valid credit card in this account to buy apps in marketplace because it doesn't let me change to my country.
My secondary email has a Zune Live ID with the correct country so i guess i will use it as my main email account in the Lumia.
I don't own a Xbox.
At least, is it possible to add another email account the the email program and use it to send emails by default. like i do in Outlook??