I like all 3. They show well for me.
Could you create a version in which the graphic aslo contains the "G"? HG or Hg. I'm wondering if that could be done while maintaing the elegance of this look.
I'm thinking ahead here to where a "sportier, hipper, web2.0" version of the logo in a follow-on contest for the high school seniors site could maybe feature a more prominent Hg as in the chemical element symbol for Mercury. I hesitate to mention that here, because I don't want this effort to derail -- and I'm not sure that even make sense for that logo...
BTW, an elegant look that I have liked is from:
http://blog.rickferro.com/