While working [1] last night on mod_blog, I also gave some thought to navigation and when to apply it. I figure the easiest way to handle this is to only apply navigation when the user selects either an entire year, month, day or single entry. In other words, when the user doesn't select a range of entries to display.
Later on, I can then work out how to handle navigation (“Next” and “Previous” links) on arbitrary ranged requests.