Whats the best way to handle and monitor multiple email accounts without using desktop applications such as outlook?

I have many email account on different domains, on gmail, yahoo, hotmail, aol, and my company email account.
I don't like applications that download my emails on my PC such as outlook, i like to manage them through the browser.
What i am doing now that i open a new browser window and open all my email account in its tabs and keep always this window open.
Is there a better way, can you share you experience.

From web app Amr ElGarhy

• Simply setup each mail service to forward your mail to one primary email address. For example I forward everything to my gmail.

  On each mail service, I will try to mark all incoming as read and forward a copy to my main mail services. That way if I ever need to reply from a specific domain I still can.

  Amr ElGarhy : and you reply all from gmail?

  Brian R. Bondy : Yes unless it's very important that you reply from a specific domain, then in that case you can login to the site in those hopefully rare cases.

  jfoucher : Gmail also allows you to send email using another address, making it appear as though it came from your other address to your recipient.
  From Brian R. Bondy

• You can use Gmail to manage your emails. Gmail can send & receive emails from other services (like Yahoo,Live or any Pop3 mail). in Gmail just go to settings>Accounts and Imports and start importing your mails.

  You can use your original mail to reply emails, also you can tag your emails to organize better

  ErJab : But GMail allows you to add only 5 POP3 accounts.
  From Hameds