Are you looking to spend 450$ on those 3 pieces or on your whole computer.
And if your going to be gaming your going to want a good GPU no matter what.
So build 3 is a no go.
I would say the first build is the best for gaming in general, do you have a case, hard drive, optical drive, or RAM picked out yet?
Oh and is operating system in your 450$ budget or do you already have an OS