I read a lot of people kvetching about the power supply and I just want to set the record straight (or at least not so skewed). The power supply is more than fine for this machine.
Let's look at the components and the wattage that they draw.
First, the primary drain of any pc with a discrete graphics card. This one draws a whopping 18 watts.
The cpu draws 95 watts under load.
Take in the rest of the unit, and let's assume that you're running everything else at max load. You might draw another 150 watts based on the architecture.
So, that's a 270 watt draw under 100 percent load, which, quite honestly, if you're buying this system as a stock machine, you're not putting it under 100 percent load.
tldr; The power supply for this machine is fine, as long as you're not modding it. If you plan on putting in a new GPU, then you should spend 50 bucks and buy a 500w power supply.
Edit: I used an online psu calculator and found a recommended draw of 288 watts under 100 percent load: