[Osiris]

I absolutely love the mail client in Opera. In fact, it's the primary reason I still use Opera as my main browser. At work I use Chrome because we use our own webmail client (same one we sell to customers).

I have six email accounts setup in my Opera, all using IMAP. There's a unified INBOX so I can check all my messages, but still be able to review each INBOX separately. Email search is BLAZING fast, the fastest search I have ever used, though it lacks advanced search options like searching only in the subject.

The contacts view is also awesome. Click on a contact and it'll show all the mail to and from that person, instantly. No searching.

The best part is that I never have to "check" my email. Opera notifies me as soon as I get an email (thanks to IMAP) and I keep open the sidebar on the right so I can always see the UNREAD counter to know if I have new messages or not.

Since reading email and browsing the web are things I do all the time, it really makes a lot of sense to me to have those two activities live in the same window and use the same tab navigation system. I love it.