I've seen some people referring to CM 7.0.3 as the latest stable build over the last couple days, which is no longer the case. CM 7.0.3 has been outdated for about a month now, but both some elusive bugs and some emerging features (like USB host!) held up a stable release of 7.1.
As of 6/27, 7.1 stable is live:
http://cm-nightlies.appspot.com/?device=encore (stable releases end in "-signed.zip")
The main noticeable advance in 7.1 over 7.0.3 is that deep sleep is working, meaning that there's little or no battery drain when the NC is not in use.
Edit: d'oh! The current signed version is actually a release candidate, i.e. a "We think it's stable, let us know otherwise" release. Everything else above still applies.