Links

AlphaQ.150m.com
AlphaQ's non-Counter-Strike: Source related website.

Counter-Strike Server Maps
Great place for downloading maps.  I used to get custom Counter-Strike maps here years ago.  They have updated since then and no offer a wide range of maps for Half-Life games.

DirectX 9c
The latest DirectX that you will likely need to play much of anything

Gametiger
Search for players, servers, maps.  Before steam this was the way to do it.  However if you want to search for friends, this will work better than steam (as steam friends does not work).

HalfLifeSource.com
This was the place to be to find out when Half-Life: 2 would finally come out.  Unfortunately since then, there has not been much else happening here.  If there are updates to steam or new mods, they may have some info from time to time.

Steam Download Site
Don't have Steam?  Get it here although you need to register on some website first before you can get it.

www.counter-strike.net
From the creators of Counter-Strike

http://forums.steampowered.com/forums/showthread.php?s=6eda99a332...
If you are looking to set up a HL² steam dedicated server, this gives a very good tutorial.

http://www.forumplanet.com/counterstrike/topic.asp?fid=4955&tid=1572730
This is another good website for help with setting up a HL² steam dedicated server.

server.counter-strike.net
Interested in starting your own server? This is a great place to learn and get some tips.