Suggestions on virtual survival?

So,

I'm a great fan of survival type games and have been wondering if anyone has some game suggestions for me? I tried I Am Alive, but found it waaay too linear for me. Don't get me wrong, I enjoyed it, but I didn't get the thrill of feeling like I'm surviving on my own.

Notrium was a shining example of what a survival game should be like and I played the hell out of that game. I'm currently helping a guy with graphics for a Notrium mod, though my university work ramped up recently and it's been slow going.

Anyway, If anyone knows of some good open survival games, with lots of flexibility and an actual challenge, please inform me? I doubt I'll hit gold with this, but it's worth a try.

Have you tried the Day Z mod for ARMA 2?

Sigh... I wish I could Play DayZ, but if you check in general discussion, the thread "frustrations from behind a proxy" explains my predicament... But basically I can't do anything that requires UDP ports.

probably you already played it,but there is minecraft,and in Fallout New Vegas there is a ''survival mode'' that makes you eat and drink in order to survive

Yeah, I love both games, but minecraft's survival aspect isn't really a challenge. But yeah, Fallout NV's survival was fun (If you had the right survival mods, the default was too imbalanced).