From ActionTrip:

Yep, it would appear that the creators of the FPS/RPG, S.T.A.L.K.E.R. are about to unleash a huge update for the game. Anton Bolshakov, S.T.A.L.K.E.R. project lead, said, "We're preparing a big update with a new game mode - Freeplay, with no story tasks, including only the A-life driven ones, where the goal is to gain ranks, climb up in rankings, so as to become the best S.T.A.L.K.E.R. in the Zone."

No specifics were revealed, albeit some hints were made in terms of the developers finishing the single-player SDK, which means mod creators might have something to look forward to.
Freeplay mode?! Oh HELL YEAH.

That is something I definitely wanted, just to be able to roam around without having to bother about the story etc, just explorin' & killin'...of course, cars would be nice too!

Like I've said before, I'm not going to re-play for a while yet, I'm waiting for updates and patches and such, and this is definitely a patch/update to wait for ... plus I'm obsessed with the SexBox369 right now anyway.