For the highest-quality rendering of molecules I recommend the freeware Pymol program.
There is a learning curve. Here is an image of B-DNA from Loren WIlliams' 355D coordinates, emphasizing the two layers of the
water/sodium spine that stabilize B-DNA. The green base pair step shows substantially roll. Here is the script that was used to generate the
rendering, which was then ray-traced with pymol.
