Is this worth buying?

Nightblind249 Asked: Is this worth buying?

I'm trying to think of a way to build a computer rather cheaply, I would like to use this system hp pavilion p7-1003wb from wall mart. It comes with all of the things you need for a computer including the OS and the monitor. I also wanted to add a graphics card either a Nvivdia 560 or ati 6850 and I would need a least a 700watt power supply. The advantage I see in going this was is that I would have a system that I can use until I can upgrade it. More a less a gaming rig to play the following

To play now
SC2
GW
RIft
Oblivion

upgrade to play (when I have more money)
Diablo 3
Guild Wars 2
Skyrim

or just go buy a gaming rig?