Another reason condorcet voting is nice is that there is no need to group "similar" items together. Condorcet voting eliminates the "spoiler candidate" effect, so having N almost identical entries won't adversely affect that "group" (by spreading out the votes for that "group" among more "sub-entries" than for "groups" with only one entry in it).
 
So actually I don't understand whey the logos are grouped at all, they could all just be listed individually, and then people can put them all at the same rank ("make tie" in the interface) if they don't care which one of the group they want, or they can differentiate between them if they like. You could possibly name them "60 a", "60 b" etc. to indicate that they are similar, but there's no reason not to allow people to differentiate between them if tehy so choose.

I agree with this. There are some groupings that seem arbitrary. For example, a number of entries are grouped together, because they use the same graphic with different colors. I think color is an important part of a logo. (Many companies have a recognizable color scheme that covers more than just their logo. See sun.com, microsoft.com, etc.) It will be a major factor in my vote. I don't want to vote for a design that may have more than one possible outcome.

As for what Johan said, it's definitely helpful to see logos on black and white and in different sizes.

Sean