Rug and wall color problem?

In a modern room, I'd avoid any type of area rug with animal prints or wild patterns. Modern/contemporary is about color blocking or swirls of color. In light of that I'd choose an area rug like this modern bistro area rug or this Chelsea PFJ area rug.

I would use grey on your walls. If you want to liven the room up a bit, you could do a feature wall with wallpaper. Wallpaper is huge right now, and you can find any variety of patterns and colors. I'd chose a wallpaper with black/grey/ and a bit of red in it. Something that truly pops.

Offset the grey with white or black photo frames, or choose one very bright painting that has your shade of red.