The thing is, is who in their right mind would pay ?2210 for 3DSMAX, if they only person that is going to use it, is themselves? Who is gonna pay such money for these programs?
That is where everything is going wrong in my opinion. Things are too damn expensive.
The only game which doesn't seem to be affected by the engine update is HL2. Which is why people who map for HL2 haven't had any stupid errors in Hammer.
It's not the sky I'm sure, and it's not the cubemaps being too close together mainly because the sky texture and cubemaps are in the same place as before the engine update. (And they worked fine then)
create a shortcut to hammer and put -dxlevel 80 in the command line like this : "C:Program FilesSteamSteamAppsAccount_namesourcesdkbinhammer.exe" -dxlevel 80
Point_Spotlight isn't considered as a light to the Source engine for some reason (I think). So just add a normal Light entity somewhere and it should fix that mat_fullbright problem.