Thanks to Greasemonkey and Userscripts.org, I am now a proud owner of the Meebo Message Notification, by T Fast, which will blink the browser window running Meebo to alert you to an incoming message. This makes it more like IM, which is very good at visual alerting.
In preparation from starting chat reference on Meebo, I'm also looking into PhraseExpress, which will put commonly used phrases at your fingertips, like Word autotext, but usable from any program (including websites). It seems to be an icon in the system tray that you can use to select the phrase.
I'd like to use this to put a few chat-handy phrases such as, "I'm still working on your question, can you wait a little longer?" Silence is so loud in the chat world.