The engines, languages, and commands used by pros actually generally involve all of the above. That is to say that if it exists, it is being used, has been used, or will be used by some big development house somewhere.
Outside of that, there are a number of languages and engines more typically used. If I'm wrong in any of the details here, please someone correct me, as I am still learning myself.
Graphics
1. Unreal - This engine is still used here and there. If I'm not mistaken, some of the newer titles in the Grand Theft Auto series use this.
2. Unreal 2 - This engine is being used all over. Sigil Games ([href]www.SigilGames.com[/href]) is using it to develop Vanguard ([href]www.VanguardSoH.com[/href]). There are many other titles that employ this engine, however I've been broke and out of the loop too long to list them.
3. Unreal 3 - Believe it or not, yes, this is already in the works. As a matter of fact, it is nearly complete, and there are a handful of folks developing now with it. I can't say much about this in the way of details, but let's just say that when you see the normal mapping and shading this engine is capable of, you will most likely faint. One low end object in this engine supports more polys and raw data than the entirety of any of the most complex levels made using the original Unreal engine, including all objects. There's a video out there somewhere that can give you a bit more information if you're saavy enough to find it.
4. Quake - dead... moving on...
5. Half Life - See Unreal 2, and swap out the names.
6. 3DSMax - Anyone have a spare $3k sitting around that I can have for this? This one is used literally by all the big houses, with one exception...
7. S3D - Does Sony ever lease their in house engine? God I hope not...
Physics
See above... Of course, more often than not the physics for a game are either made from the ground up or are heavily edited in house.
File handling
See Windows API... Just kidding! Actually, this is almost always done in house for security.
Communications/ Networking
See IBM, Microsoft, Oracle, Sun, etc...
Am I forgetting any of the libraries almost everyone at the top puts their hands on?
The direct x runtime often is only used in reference through a wrapper or shell in the engines above, but a knowledge of the SDK is all but required to work at all in industry standard development.
The DirectX SDK is free, and has a completely open liscence. You -WILL- need a C++ compiler to use this, and if I'm not mistaken, it's about impossible to use the DX libraries with any GNU compiler (as opposed to Microsoft's compilers).
Edit: I forgot languages!
C++ is the standard for engines.
C# is the standard for interfaces, although whether it is used is hit or miss with varying companies.
J# is the standard library for networking UIs and installation routines in .NET, both of which are libaries for C++ with enough unique data types and commands to pretty much be considered their own language.
Visual Basic -- is typically not used by big houses... I know someone will breath fire at me for this one, but name any major development house that is known to rely on VB.
VBA - No. Not at all. Not by anyone. Ever.
PERL - Networking, and complex calculations that require too much processor to let language quirks slow it down. I will have to learn this one soon.
JAVA - User Interfaces... This is replacing C# as the standard for interface coding because it is much more flexible in terms of end user customization.
PASCAL - Networking, generally, although I believe that this is usually only used for LINUX-run applications and routines.
You have a memory like trying to catch water in a steel trap. - A friend