Is there a stable email client or email client plugin that will support GMail-like conversations?

Question

Conversations in GMail are such an incredibly simple yet powerful way to look at mail. I get about twenty emails a day from various clients and I hate looking at a flat file of all emails, and I hate looking at "per client" email folders. With GMail I can just look at a specific conversation. I can see a few lines from each in the collapsed titles so that I can quickly remember what was said previously, and I can expand them if I need details or need to quote something.

But I can't justify using GMail to handle sensitive work emails, and we need to be able to access all my emails offline. So what do I use?

Answer 1

Outlook 2010, still in beta, has a new Conversation view, as described here:

Manage large volumes of e-mail with ease

Conversation view in Outlook 2010 improves the tracking of e-mail conversations—reducing information overload—and helps you manage large amounts of e-mail with ease. Entire conversations can be condensed and categorized with a single click. And, new conversation management tools enable you to save valuable inbox space by turning dozens of e-mails into just a few conversations using the Clean Up feature. Or, use the Ignore feature to send the entire conversation to your Deleted Items.

Of course, a Beta version does not qualify as "stable", although it has been very stable for me so far.

It supports of course retrieving emails from GMail:

You can easily manage e-mail messages from multiple mailboxes. Synchronize multiple e-mail accounts from services such as Hotmail, Gmail, or just about any other provider to Outlook 2010. Improved connectivity with Microsoft Exchange Server supports the use and management of multiple Exchange Server e-mail accounts in one location.

Answer 2

There is a plugin for Thunderbird 3, called Gmail conversation view.

Answer 3

How about postbox?

Answer 4

Thunderbird has conversation threading and neat tabs now too, I think.