At our first round of absence_oflight, we had judges for each category, awarding 1-3 places, depending on the number of nominees in the category, then also had a 'fan favorite' which was popular vote. And really, if you use GoogleDocs, Pop Vote is about as easy as Pie, plus you have the judging side that IMHO does have more credence, simply because the person judging (is supposed to) actually READ all the entries, which 99% of people who do pop vote don't do. It was very interesting to see where the pop vote and judges agreed (and disagreed).

You could also do the opposite - pop vote, then have a Judge's Choice for each category or some such.

That said, if I have to choose, I go Judged, ALL THE WAY.