There exist two options:

1.) Have all mail automatically forwarded from one account to another using the options provided by the e-mail service.

2.) Use an e-mail client, such as Microsoft Outlook, Mozilla Thunderbird, etc, to aggregate all e-mails into one, easy-to-use location. This, however, requires the e-mail service to support POP3.

Now, Gmail supports such functionality, but most free e-mail services do not...Yahoo and Hotmail are examples of these. For that ability you would have to pay a monthly/yearly fee for a 'premium' account.

In short, you may be able to do it for some, but unfortunately you won't be able to dwindle it down to just one account you have to check everyday.