How can I see the status of my favorite servers without logging in to the game?

I have a short list of servers that I visit whenever I play TF2. Sometimes these servers are well-populated, other times completely empty.

When I unwind at my computer, I'd like to check to see the status of those servers before launching the game. How can I see how many people are on a specific TF2 server without using the in-game server browser?

Solution 1:

You can right click on the Steam icon in the System Tray (next to the clock) and select servers, and this useful tool will come up :

There you will have every server, grouped just as you did in-game for every game you own.

You can also access it this way: