I'm playing through the first one again with some mods.

I'm using:

-Sharper Textures http://forum.v5g.de/showthread.php?t=10034

-Improved skies http://stalker.filefront.com/file/STALKER_Skies;80755

-Flashlight extender http://stalker.filefront.com/file/Flashlight_Range_Mod;78115

-Traders repair weapons/armor http://stalker.filefront.com/file/Repair_Mod_Rus_Eng_Ger;78100

I tried using the "Increased weight limit" mod but that one seemed to break quick saves so I had to take it out.