A nice quality stuff!
My favourite image would be the last one (which you posted on 04-02-2012),with a room lit by a nice gloomy light.
Well as far as critics are concerned there is not much to be done in your images they are quite nice. However, I will personally like to see a bit more bounce light and the light seeping through tree leaves in the forest image(4th image).
Last but not the least I think the rays need to fade out a bit or disperse a bit more in the forest scene. There are few bits here and there but as you know it's hard to capture every single detail in the nature.
Looking at you images made me wonder what computer configuration and renderer are you using, a bit information about render time and overall working hours on images will certainly help!
Shashi Kant Negi