Amy,
Nice job on your web site! It looks very good.
I like the general design and your black and white scheme too.
You had mentioned you are going to add an image to the site and make it greyscale. I immediately thought it would be kind of neat if you can have most of the image greyscale and perhaps one part in color....
For example, if you had a picture of a desk with a flower pot on it. You can have everything but the plant greyscale. Maybe make the plant pink or something. I am pretty sure you can do this using Photoshop by manipulating layers.
The images on your portfolio page really pop in relation to your overall color scheme, so that is what gave me the idea.
Anyhow, just my thoughts. Nice job!