If all you're going to do is set up a Blogger account or a basic install of WordPress, no don't do it. It looks cheap, unprofessional and unoriginal.
I've seen some portfolios that are run on WordPress or TypePad or whichever one I forget and you'd not be able to tell it except for the "Powered by" credit at the bottom.. In these cases, I think it's great because you get the best of both worlds: Original design & CMS.
In my case, I don't need the power of Blogging software, so I usually power my portfolio using basic PHP I write myself, which handles it dynamically just the same but saves me the time of having to skin WP.