the site i used is not the cheapest possible, it is somewhere in the middle ground. So depending on what can be reused from another computer (PSU, HDD) you should be inside your budget.
@ Trotskygrad:
i lol'd how we created a post on the same time (exactly)
@ gotya2: If you use a AMD CPU instead of an intel CPU, you can also get quite a decent CPU for that price [like this one]. You may need a new mainboard then too, though [like this one]. Also, the Harddrive is slightly overpriced. You can get quite a decent 1TB HDD starting at ~60€ [like this one].
Also, I would take the Corsair CMV8GX3M2A1333C9 as ram. Costs 10€ more, but has 8GB.
That will again have saved up to 20€ with partly even better specs.
True that, i'm sitting at 520 at the moment so u can consider 8GB of ram, but it really depends on what u want.
If u really want a gaming system, focus should be on the graphics card. I would get something better than hd7770.
You really want to go for an Intel instead of the fx 6100 .
I'm not an intel fanboi but this entire "more cores = better" is rubbish for gaming applications.
More cores is better, not neccisarly for gaming (since most games use only a single core) but in general more cores is better, just like a higher clock frequency is better.
Buy SSD Harddrive. Yes, it costs more, but if you get it and install some OS on it, you won't regret it.
I just suggest you to buy some SSD for OS, and then another HDD for random crap you got.
NOOOO! I have a 256GB SSD with my operating system and some programs and honestly, it's not that much better than a hard drive. Yes, windows 8 boots within seconds, but do you really want to spend so much more just to save 10 seconds???