3D is no biggie, any current gfx card should be able to handle it. Regarding the GTX 460 and HD6850 they're about the same powerful with the 6850 being newer & overall a tad bit better, so I would go for it. For the "Nvidia" experience (better drivers, proper 3D, CUDA...) I would get the 460 though. Really depends what you want
I'll give you my recommended stuff tomorrow, don't really have the time to check stores around Europe right now, but I think that you could get both the 560 and 6870 for around 200€ (and of those two I would recommend the 560 since it's, well, Nvidia and also generally considered "better"
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