I like Google Talk because of the straightforwardness and the fact that the system keeps a log of my messages even when I use different Gtalk clients on different computers. However, one gripe I had with Google Talk is that it did not support offline messages. Well, it does now. I was surprised to have been receiving Chat messages in my Gmail inbox since a few days ago (before, you only get to see the chat messages under the Chats view).

The Google Talk team has recently added offline messaging:

As you’d expect, this enables you to send messages to Google Talk friends who are offline. The messages will be delivered to your friends the next time they sign in with Google Talk or a third-party client. And when they sign in to Gmail, offline messages will be displayed as unread messages in their inbox. In Gmail, offline messages can be searched and organized — just like instant messages in your chat history.

You need to have chat history enabled for this to work. I do think this is turned on by default.