How to structure multiple subjects?

Hi, this is not a question on the technical issues of WordPress (yet, but rather on the methodology for organizing my stuff on the web.

I have interests in several areas, planning to start blogs on these diverse subjects and want to arrange this in a logical way. There are probably two ways to do this – set up a “root level” page with subpages per subjects, or simply totally separate pages. My subjects might be basically these:
– About myself. CV, contact info, etc. Could be that “root” page.
– Community blogs, comments and opinions.
– Hobby (amateur radio) blogs and info.
– Teaching page, for material I use in part time college teaching.
– Professional page (engineering), relating to my job.

I am starting to set up my WordPress web, but first I would appreciate suggestions on how I should structure these diverse pages – all under one “master” or “root” page, or just keep them entirely separate and unconnected?

Best regards – Kristinn