For Battlefield 3/4, you'd probably be better off spending more than 650 euros (which is about ~$860 USD)
Personally, I've become a fan of Clevo laptops. They seem to be good value and very customisable:
XOTIC PC | Sager NP7352 (Clevo W350ST)
This one comes with a dual core i5 at stock ($920 total), but you can get a quad core i7 for $75 more. I think that's worth it.
And the GTX 765M is pretty good as far as notebook GPU's go.
XOTIC PC | Sager NP8235 (Clevo P151SM1)
And this one even has a replaceable graphics card (MXM module), which means in 3 years you can put in a better GPU and not have to replace the whole thing.