If I was spending that much on a pre-built PC, I would want a better graphics card. The 550 ti is on a par with the HD 5770,4890. Both good cards in their day and if you are on a tight budget,you will still get decent frame rates, but I feel you might struggle with later titles.

I think I would also be looking for the i5 2500k CPU. Which is probably one of the best chips around at the moment.

But overall I believe the Medion name has a good reputation for reliability so if you are not into building your own then this is worth considering though I feel that you could get a better spec for that sort of money. I may well be talking rubbish as I build my own PC's so do not pay much attention to pre- builds.

Here's a reasonable graphics card comparison site you might want to stick in your favourites. GPU.