One thing I use on Ubuntu is the chat app, which makes it so if anyone tries to say anything to me using Google chat, it shows up (I don't have to be logged in to Gmail or have a tab with Gmail open). I can respond easily too.
What could I use on Windows 7? I hate having a whole tab open just for in case someone needs to chat. I couldn't find a chrome extension (which is what I would prefer, I have one that checks if I have any mail). But I'd even be fine with a lightweight desktop app.
By Google chat I'm just talking about IM using my Google account (I'm not talking about "Google talk")