maherie, woo hoo! so excited! and not long to wait either. remember Shadow of Chernobyl? Jesus that took YEARS of waiting!
And they still didn't finish it. Their publisher finally sent someone in who axed over half the game and feature to get it released. Clear Sky is going to have quite a few things that were going to be in the original STALKER. Also, for people completely oblivious to the modding scene, some essentials include better shaders for much better performance:
http://www.thefloatingpoint.org/main/download.php?list.4
And also check the GSC forums for a mod called Priboi Story, it's a complete conversion of STALKER story line, this time you're a military dude 1 year later in the zone. Plenty and plenty of mods to keep you playing for a while!
http://www.gsc-game.com/index.php?t=community&s=forums