Oh yes you're right! It is working perfectly now, I really appreciate it. The final form is:
list = []
users = system.user.getUsers("")
for user in users:
contacts = user.getContactInfo()
for contact in contacts:
if contact.contactType == "email":
email = contact.value
first = user.get(user.FirstName)
last = user.get(user.LastName)
if email is not None and first is not None and last is not None:
list.append((first, last, email))
print list