GPU, CPU and PSU!

[Steve09]

Probably going to be building myself a new PC in the next week or so.
I'm swaying towards the GTX 260, would a Corsair HX520 watt power supply be enough for this card?
Processor will probably be an E8400, would this bottleneck the card at all?

Thanks

 

[Steve09]

I was thinking about the 4870, but I've always had nVidia and don't know what the ATI cards are like. What I'm saying is, will I notice a difference in playing games on an ATI card to an nVidia card, because some of my friends have said most games are built more or less for nVidia?