How can I archive automatically on reply in mail? I'm using Mail with Google Apps (Gmail). My goal is to archive automatically the email I've just reply. Leaving me with a clean inbox. How can you that exactly? (I'm using MailTags and Mail Act-On a lot.)
Apple's Mail.app doesnt have a feature to toggle for this, but you /can/ do this in Sparrow. 

Sparrow has a lite version that might suit your needs, but the full version does what you ask.