It's really well done... the mood is what makes the picture. I feel like it's just after sunrise in some bitterly cold place, where you're losing a toe a second to frostbite, and yet you can't help but stop and watch as the sun rises higher and the water slowly ripples. Maybe it's an effect of this chilly house (though really, considering that it's less than 10 days from the summer solstice and we haven't put in the air conditioners yet, that shouldn't be possible), but this picture really evokes that mood really well for me.
Very nice, I admire the near-photorealistic quality you can get out of Terragen.
As for the snow, what looks weird to me is in the lower left where it butts up against the water. It looks like too sudden of a transition. If you look at that segment of snow, it's also a little blocky, and it has a similar transition problem with the terrain in the lower left.