1x 8800GTS vs. 2x 4870 CrossfireX?

[TrainTrackHack]

Somebody mentioned a bottleneck though, I don't want to buy it and it be effectively the same as two 4870's...

Physically though, is two cards crossfired better than one X2? Or equal?

As long as you have a PCI-E 2.0 mobo (which I believe you do), the bottleneck will be insignificant. The performance defference between single 4870x2 and two 4870s in crossfire is insignificant and not noticeable, though two single cards usually get marginally (you won't see the difference) better scores.