Shooting in low light - cranking up your ISO

I saw the shadows on my kids faces as they were sitting at counter in my kitchen this evening.  I thought it looked beautiful so I ran to get my camera which happened to have my 105 mm lens on it.  By the time I got the camera back to the kitchen the sun had already set and I lost the light.  Bummer.  But, I still liked the shadows so I snapped a few pics of Jennica.  The close up picture my ISO was 3500 way too high. . . .but it was exposed perfectly.  I then lost more light so I told her to run to the window and I took the last shot of her which my ISO was up to 6400.  When I loaded them in photoshop I reduced the noise and then ran a skin softner over her face.  That helped the grain a little bit.  I then did a pop the color on the full body pic and on both pictures I ran a defog.  Then I resized them for the web which reduced the noise even further.  Anyway, my point is that you should still take the shots and crank your ISO if you need to.  At least you have the images.  No these shouldn't be blown up big but their great snap shots.