most of sites rank PR4, the only sites that I have that don't have PR like that are my blogs and my lenses. most of my blogs and lenses have PR 1 to 3. since they all rank well, it doesn't matter that much for me for now...
I used to have a bunch of websites, most with PR.\
Now I'm down to two and my highest PR is currently PR3.
I remember when I got PR3 in less than a week. I'm slipping.
The point is that by taking a look around the web, you will notice that more reports are about losing some PR values and only small groups of sites are actually gaining or boosting PR. Google has completely adapted its PR giving algo and the relevant matters.
I don't have my own domain site yet but my blogs are performing well even though I don't update them often anymore. I guess it's because of their on-page optimization which earning them good SERP standing and consistent PR3 ranking.