Major overkill. Most, if not all, gamers I've come across rarely use anything over 2x or Quincux. I personally do not use anti-aliasing because it indescriminately fuzzes out all jagged lines but it does not take into account that some scenes need them to look correct.
-16X Antialiasing (beyond this, is it even an improvement?)
Watching the horizon in a flight sim turn into a stairstepped fuzzy affair is quite ugly.
Watching distance objects become fuzzballs because of over-anti-aliasing is equally as ugly.
This is possible with shaders. However spending oodles and oodles of CPU time on ..um...atmosphere is somewhat of a waste of resources, unless the atmosphere is a vital portion of the game....say in an RPG space-based shooter or something.
-A full atmospheric model (outdoors only, using terragen as guideline)
This can be done using shaders as well. However be careful since this produces extremely bright glares and effects. You may give the gamers a major headache with your new cool uber effect - which means most of them will whine about it or will find a way to shut it off.
-High Dynamic Range rendering
Check out Pacific Fighters by 1C and Oleg Maddox. The sun glare is major uber and major annoying.
Shaders, again, are your answer. You may not be able to per-pixel shadow everything even on high end systems. It all depends on your shadowing approach.
-Per pixel shadowing
This is already a standard in graphics. Most play games near or around 800x600 to 1024x768 simply because text gets extremely hard to read at higher resolutions. I know some that play games in 1280x1024. This is already possible on modern hardware so I would not include it as a requirement for great graphics.
Radiosity is cool when done in moderation. Using radiosity on everything simply won't look right. Radiosity, glow mapping, and hemispherical lighting all do wonders, but only when applicable. Usually per pixel diffuse and specular look quite nice.
-Some kind of fast radiosity
I have no idea what this is. I seriously doubt anyone cares if their main character's hair flows like that on the Final Fantasy movie. This, in my opinion, is a waste of time.
-Dynamic anisotropic hair (not quite sure if I understand this)