4. Email

Be sure to get the right type of email for you.   It doesn't have to be from the same company that hosts your site.  However, it is usually the easiest and cheapest solution for you.

There are two ways email is typically offered:

1. Shared Space - all your email accounts share the same space.  This is nice if a small number of people get most of the email.  However, if anyone gets a lot (even that email account that you forgot to disable), then everyone is affected.  For example, if Mary down the hall is on vacation and her friend sends her a stack of baby pictures, no one else may be able to receive any emails.
2. Space per Mailbox - each email account is allotted its own space.  This is nice if everyone receives about the same amount of email and it overcomes the problem of one mailbox blocking everyone else out.  However, the size of the mailbox might be smaller than someone needs.

How much space a mailbox needs really depends on the size and volume of attachments you receive.  If you do not receive attachments, a 5M (megabyte) mailbox will handle a significant amount of email.  To determine your mailbox size, add up the number and size of attachments that will be sitting in your mailbox at the same time (and keep vacations in mind when you are not checking email).  For most people, a mailbox of 5-10M will provide plenty of space.

If necessary, a great answer is to use a hybrid approach:  give everyone their own space (so Mary's baby pictures don't block you out), and if there are one or two people who do need additional space, add on a larger mailbox for them.  This gives you the benefits of both options for a reasonable price.