Well, just like a lot of other online users, I have fallen victim to a severe addiction to playing multiplayer games over the net.  Here's a great idea for people looking for some good inexpensive software to play games with,

    Ah yes, another 3-D shooter game, but this one does a great job.  Just playing the singer-player (at home) game is enough, but they've gone on to do even more.  It comes with a copy of Worldcraft so players can now create their own levels for Half-Life.  Some are good, and some are terrible (like mine so far).  The CD also includes the Sierra Utilities auto update software so once you get online it becomes really easy to upgrade with the most current patch.  A lot easier than with previous games where you'd have to know where to download the files to their corresponding directories (makes it a bit more idiot proof).

    A very popular addition to Half-Life would be Team Fortress Classic (TFC).  Just like with Team Fortress for Quake, TFC for Half-Life is incredible.  I never did get into the TF frame of mind when playing Quake, however with Half-Life I've almost forgotten how to play the single player version since I'm online so much playing TFC.  Here are some sites for Half-Life and TFC that I strongly recommend, especially if you're looking to get some maps (Radium does a great job).