My blog designs portfolio site is on a subdomain of my WAHMaholic blog. It already has a PR1 and I think it's quite comfortable where it resides now. However, the OC in me insists that I get its own domain. It doesn't get a huge amount of traffic, don't get me wrong, so I don't think I would need business web hosting anytime soon. I do want a more professional feel to the site, though, and for me that includes a website's own .com domain.
Of course I know I will lose its Page Rank if and when I move, and that's one of the biggest factors that's holding me back. Added to that is the fact that I need to market the new domain again to make it known to new and old clients. And it would need a new theme as well. Oh dear. That's a lot of work for someone whose time management is not the greatest in the world. aybe I'll just sit around, wait and see. No one's forcing me to move anyway.