I occasionally get added to endless email conversations which I have no time to read and/or contribute to. If I archive the message, it will pop back into the inbox every time someone replies and sets off the GMail notifier. However, I recently discovered that GMail has a nice ‘mute’ feature, which archives the message and means that even if people reply to the conversation, the conversation will remain archived and will not pop back into the inbox. To use this, just press ‘m’ (mute) when viewing a message instead of ‘e’ (archive) and the conversation will be muted forever. If you’re not a fan of keyboard shortcuts, you can get to this via More actions when viewing an email. Note that if you are worried about missing emails directly sent to you within the conversation, you might want to check out the smart mute feature in Google Labs. Finally, to view all muted conversations, you can just type is:muted into the search box.
To see a full list of all GMail keyboard shortcuts, see this page. If you want to customize keyboard shortcuts, you’ll need to enable this in GMail Labs, after which you can go to Keyboard Shortcuts under Settings.