I am looking for an email app other than Apple Mail for OSX Lion. I use Apple Mail for work, and don't want mix my personal email with my work email app. So I need to use either Thunderbird, Postbox 3, Outlook 2011, or Sparrow. I have a Gmail account, a Google Apps account, a yahoo account, and a standard IMAP account. I don't generally use the Gmail web interface, so most of the web interface features don't matter to me. What is the best option, that is good, quick, and I can search quickly?