I'm so sorry! I totally missed your original question! "Marble" is described on Smashbox's website as "soft brown champagne". Bronze is apparently a bit darker and probably warmer because it has a copper undertone. So between the two, you'll probably get a more dramatic look with Bronze, and a slightly softer look with Marble.
Here are the Smashbox color descriptions: http://www.smashbox.com/product/6025/22955/Eyes/WATERPROOF-SHADOW-LINER/New/index.tmpl
It really depends on your individual coloring (warm toned or cool tones? Pink tones in your skin or olive? etc) but traditionally, browns/coppers/bronzes are recommended to emphasize blue eyes. If you like the way brown/copper shades look on you, you could try Bronze or Marble.
If your eyes have any hint of green or if you have green flecks in your iris, you would probably look great with Luminous Fig. Another reviewer said that Luminous Fig was a great shade for her blue eyes.
I have mixed results using plum shades with my darker, "flatter" (i.e. less luminous) medium-blue eyes, but I'm going to give it a try, along with "Charcoal", since a shimmery, steely gray can also be good for making blue eyes really pop. Since my eyes are darker blue than most, I have better luck with metallic grays than anything else.