Yes, email providers vary greatly. Some are free, some are not. Some offer POP and IMAP, others like Hotmail only offer it to paid users. (If you want to use an email client like Outlook or Thunderbird, this is important to know.) Some have great web interfaces, some have no web interface. Some offer filtering, custom mailboxes, superior spam fighting, etc. If you're unsure, I'd suggest considering Gmail as the standard and going from there, based on your needs.