2 Models and some questions.

[Titan]

Here's a couple shots from my shoot yesterday. This is the first post from the new camera (Nikon D50). And Im wondering what some of you think? Also I have a couple of questions.
First and probably the most obvious. The window blind. At first I thought simply closing the blind all the way would be enough to diffuse the light (is diffuse even the right word here?), but looking at the finished photo I can see that I probably needed more? A sheet inside the blind perhaps? Al Nowak suggested using a shower curtain or white trash bags and I'm wondering if that would have worked here.
A related question, is the white in the background so bad that it kills the image, or does the image work okay the way it is?
Which is better color or B&W?
Any other suggestions or comments would be appreciated.