^That... is a bloody impressive budget build.
However, if it is the case that the OP has nothing, then he's screwed.
OP, consider it like this: When you set out to go kayaking, you have a choice of kayaks, right? But first you have to get your paddle, gloves, wetsuit, and things such as these.
The monitor, mouse, keyboard, and often OS are these equivalents. They're the requirements to get in the game, and are much of the up-front cost, but will stick around through however many upgrades you have in the future.
I'd suggest going with the $600 build above, and funding the monitor, mouse, and keyboard from a different budget. (I personally spent about $600 on those three parts - a $400 3d, 120Hz monitor, a $60 mouse, and a $140 mechanical keyboard. And I have to say, I don't regret spending a cent of it.)