Thanks for your entry!
While we like these designs (particularly #3), we feel that both design #3 and #5 have something of a corporate feel to them, and we are a grassroots, community-based non-profit. #5 is a touch too slick and non-organic feeling. Because the Washington Monument is such a symbol of power, it's very important to us that this be undercut/overgrown with organic and natural components. #3 feels like it has potential. We like that the design is clean, but as an organization, we are involved with gardens and plants. We'd love to see some plant elements introduced into it.
Thanks again!