Does God really need us?

Especially since he's allegedly all powerful and all knowing and could destroy everything at any moment if he felt like it.... Not to mention, why would he need others to fight a spiritual "war" for him if he could easily defeat his enemies? This question was asked before and someone answered : "He doesn't need us to worship him. Its something we do to profess our faith, show our love and gratitude." If this is the case - then why would a God be selfish and tell people that they shouldn't have any other Gods before him? I really am trying to understand the Christian perception of God but it's just so far fetched, from my point of view, that I can honestly see why people become atheists. Please note that I'm not saying your God or religion is invalid because I don't believe that at all. I think Christianity does a lot of good for a lot of people. It just isn't for me. And one of the reasons is because I just don't *get* the Christian concept of God.