I'll never forget the sinking feeling of dread upon realizing the entire mating ritual of a beautiful Peacock display was shot at ISO 1600. At the time, I was mortified, having forgotten to change the ISO from a late night baseball game the previous evening. This was back in 2005 with my first DSLR, a Canon 10D, not necessarily known for it's high ISO performance. Thankfully, noise reduction was an easy fix then, and has continued to improve over time.
The shot was indeed grainy as you can see in Example 1.
As you can see in Example 2, the file cleans up remarkably well with noise reduction in LR4. The settings under noise reduction were:
Luminance: 100, Detail: 70, Contrast: 0.
I then used a small adjustment brush to sharpen the eye and a portion of the bill, added a touch of vibrance, and presto!
To recap, this was taken at ISO 1600 on a Canon 10D which sells for about $100 used today. I'm including a large sample above so you can really see all the beautiful detail.
This is just another example of why we need to break away from the constant bombardment of magazine ads, and pixel pushers. Your current camera is good enough, the trick is to learn how to control it. Noise is not as big of a deal as manufacturers would like you to believe.