email overload

I’m having email overload and am starting to both miss and lose messages. I unsubscribed from all that I could. I currently use a painful combination of Mail, thunderbird, and gmail. I want one application which can handle multiple accounts easily (in IMAP), properly send attachments, and not lose messages. Tie-in to my calendar is a big plus.

Right now I am seriously looking into Entourage. *sigh*