shouldn't we have a list of games or demos to try that we KNOW causes artifacts in defective cards?
Well, the only problem with that is everybody seems to be having problems in different games. I can say that the OpenGL version of Unreal Tournament 2003 is probably one game where several people at least on this forum reported problems with. We could say try UT2003 then. Not everybody have the same games however, so that is another problem. Some people might have a whole bunch of first person shooters but not UT2003 and might not want to buy UT2003 just for artifact testing. In my case, I had problems with Soldier of Fortune 2 and Urban Operations but no problems with any other game including UT2003. Nobody else reported problems with the games I had problems with though. You see, since we have most of the problems with the HyperZ units on these cards as opposed to the 4 extra pipelines, depending on which part of the HyperZ unit is defective, people will not be getting artifacts in the same games in the same fashion. HyperZ unit is something pretty complicated and it is very unlikely that everybody would have the same kind of defect in the unit.
As a result, some people report problems even on the desktop whereas other people report problems with only some specific games. The list of these specific games change from person to person. In the end, just try whatever. Run 3dmark2001 or 2003 for directx app1 (since it's free everyone can just download it and run it), UT2003, Unreal 2, Warcraft 3, FIFA200x, Neverwinter nights, Command & Conquer generals, Max Payne or whatever for Directx apps 2 and 3. Most games on the market are DirectX games so if you just have 2 DirectX games that are not very old, you completed the DirectX list.
For me, thinking of OpenGL games is much easier. This is because there are tons of games out there that use the Quake 3 engine and run in OpenGL. Examples are Quake 3 itself and then: Return to castle Wolfenstein, Medal of Honor, Urban Operations, Jedi Knight 2, Soldier of Fortune 2, Battlefield 1942, etc... If you have UT2003, again you can run it in OpenGL mode as well as DirectX mode having shot 2 birds with 1 stone. Actually, I think with so many games running with the Quake 3 engine on the market, you are likely to have a couple first person shooters that run with OpenGL. And if you need a Radeon 9500/9700 card, chances are that you are into first person shooters as they demand the most from graphics cards (as games, not talking about professional 3d applications).
Having said this, I don't think it is very diffucult to find 3 OpenGL applications and DirectX applications for testing. 3dmark takes your requirement down to 2 and then UT2003, if you have it, counts both as a OpenGL app and DirectX app and there might be other games out there that also support both DirectX and OpenGL.