The advent of "e" before a dictionary term has had it's ups and downs. For the most part the "e" domains needed serious marketing to be great. Some of the short ones are so prosperouse and made for it though. I like eDomains and think moany hold high value.
I think "o" would be a tougher sell to be honest. If your hell bent on making money from it. Make a site befitting it, and have a very nice banner made emphasizing the "o" and what it means. Then use that to sell it on ebay to someone who thinks they can use it.
Value to me ( I wouldn't hand reg them ) And I wouldnt make the effort to make them a viable site.
I might not sound so inspiring, maybe someone can come back wth something more creative as the day runs on.
Wish the best with them.
Jack