It really seems to depend on the frequency of updates. This blogger account usually updates immediately, while I have a Wordpress blog that I update less frequently that often takes 24 hours to have new posts indexed. Other Wordpress blogs I have get updates indexed pretty much immediately
This seems true, as well for my Orange County SEO site which, despite its PR1 status, does not index as fast. I don't update it that frequently. Mostly, I target it for real estate SEO. Changes in my core strategy are not daily, so updates are not necessarily frequent.