I most definitely prefer your second version, the gold, the best.
One thing about the brick red though is that red definitely does stand out on shelves well. It also matches the DDN theme and I suppose that's why you came up with that design first. Since the book will most likely be turned on its side for display, there is an option between the two (the brick red and the gold) that I came up with for you to consider. It may be more expensive to print the cover this way though, I suppose.
I'm not sure if I like this hybrid more than the second version (gold), but, this way the binding is still red and will stand out accordingly.