MicTig, I really appreciate your detailed response.. Because unlike some posters - you spell out the problem in detail. I think that people who trash GNU/Linux without providing any specific details, are motivated by something other than making computers work better for people. Like the person who said one can take much time to get software working on Linux, well I'm here to tell ya - I have experienced the same type of software problems on many different OSes, i.e., Windows, Mac OSX, Solaris, yes and even Linux. To say as a blanket statement that one can only experience software configuration problems in Linux, is rather ignorant and totally baseless actually.
I fully agree that there are certain applications that don't work (yet) with GNU/Linux... and by providing a specific list, you are helping to solve these types of problems. GNU/Linux isn't for everyone, yes it's true.But if you're a person, who like me, has seen many iterations of users being sucked into the proprietary software model(and chewed up by it) - only to see their computers burst into a security mushroom cloud of a meltdown because of crapware and malware like the Vundo and Smitfraud root-kits spewing volumes of traffic across port 25 to mail servers in other countries... than I'm here to tell you... there's nothing better than the FREEDOM of GNU/Linux. And besides that, try losing your License key, or forgetting to "activate" for Linux...lol.. not gonna happen - because you don't have to use these types of restrictions.
GNU/Linux isn't for everyone, but it is for those who want to benefit from the contributions of humankind to computer science, and it is for those who want to get satisfaction from using computers again.
As for the software you outline, some work in WINE, like L4D for instance - see this video:
www.youtube.com/watch?v=far0jjAlg24 and others don't (yet) - but you can be sure of one thing... for every new user to GNU/Linux - the better things will get. Also, as for performance - I've seen some say that certain games actually perform better in WINE. And Linux may not be the "Fix-All", but supporting Computer Science, and not trashing it with greed, should definately get you closer.
Please also have a look at:
[http://digg.com/linux
unix/OpenLetter
toGame
MakersInvestigate
theGNU
Linuxniche]
Here's some more information for you to check out(like I said, some work, some not):
Garry's Mod - [http://www.youtube.com/watch?v=ji4KlTGeaAw]
FlatOut Ultimate Carnage - [http://appdb.winehq.org/objectManager.php?sClass=application&iId=7964]
Prototype (not sure this is right) - [http://appdb.winehq.org/objectManager.php?sClass=version&iId=14629&iTestingId=34575]
Rainbow Six Vegas 2 - [http://appdb.winehq.org/objectManager.php?sClass=application&iId=7099]
The Sims 3 - [http://www.youtube.com/watch?v=NE8c_8fsN3U]
AA3 - [http://www.youtube.com/watch?v=YIRrHSyLuTI]
COD WAW - [http://appdb.winehq.org/objectManager.php?sClass=version&iId=14475]
Combat Arms - [http://appdb.winehq.org/objectManager.php?sClass=application&iId=7960]
Dolphin GC and Wii Emulator - [http://appdb.winehq.org/objectManager.php?sClass=application&iId=8021]
HAWX - [http://appdb.winehq.org/objectManager.php?sClass=version&iId=15906&iTestingId=38479]
Please also have a look at these GNU/Linux gaming resources (most have FREE games):
[http://www.lgdb.org/list_games]
[http://www.linuxgamepublishing.com]
[http://linux-gamers.net]
[http://icculus.org/lgfaq/gamelist.php]
[http://happypenguin.org]
[http://www.linuxgames.com]
[http://tombuntu.com/index.php/2008/09/02/playdeb-the-gaming-repository-for-ubuntu]
[http://www.dedoimedo.com/computer_games.html]
World of Goo (awesome game) [http://2dboy.com/games.php]
And finally, see these links for more examples and videos:
[http://www.humans-enabled.com/2008/11/dell-inspiron-530n-nvidia-9400gt-ubuntu.html]
[http://www.youtube.com/thecoolguy4linux]