In general, I'm going to leave honorifics like "-san" and so forth as they are. I think most people (especially people who would be reading this blog) have at least a passing familiarity with Japanese honorifics, and so trying to shoehorn them into the English system -- drastically altering the effect of much dialogue in the process -- makes little sense.

For those who don't have a passing familiarity with them... uh, sorry. The wikipedia article linked above is pretty helpful, and here's a quick summary, with the inevitable caveat that circumstances and time period cause mileage to vary:

• -sama: The most respectful honorific. Used for gods, royalty, customers, and also in certain stock phrases (like danna-sama, "master" or "husband").
  
• -sensei: applied to teachers, doctors and certain other professionals. Can also stand alone.
  
• -senpai: (sometimes optionally) applied to those ahead of one in a hierarchy. Can also stand alone. (Kôhai, the opposite of senpai, is not often used as an honorific.)
  
• -san: The "default" honorific.
  
• -han: Western Japan version of -san.
  
• -kun: Usually applied to boys or young men of equal or lower rank to the speaker. Can be applied to women too, though, in some situations.
  
• -chan: Dimunitive, affectionate honorific. Applied to people of both genders, though probably more often to females than males.

Note also that I attach honorifics to the name with a hyphen (Suzuki-san) rather than writing them as a separate word (Suzuki San) like European honorifics, and I do not italicise honorifics used as address terms ("Hey, sensei! Can I borrow $20?"). Again, feel free to argue with me about this or call me on inconsistencies.