Some of the screenshots show the difference in graphics between the Xbox 360 version and the PC version. Here's a short list of what will be better in the PC version:
You can check out all the screenshots over here.
"Building, Background Ambient Occlusion" set of screens - The PC version features XSI Ambient Occlusion, which the Xbox 360 version does not. The bullet holes are more steric and deeply hollowed than the Xbox 360 version. In the PC version, the resolution of the effects are much more enhanced than the 360 version. The edge of the character's shadow in the PC version is much smoother.