Tried this on fire fox 3.5.5, had few problems with the install instructions you put in there (I am using rc1 version of the OS commerce)
<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"> works best....other ones like the loose might not be the best option (I stand corrected)
Also add to cart button. Even though its common sense, I still think it will be nice to alert people to watch out for this.
Apart from these it is brilliant!!!
Just a thought...how can you increase the size of smaller images ?
I think that will be nice to get all images to show similar size regardless of how big or small the image is.