After mulling over converting the site to WordPress MU and some other
gallery software, I decided to just upgrade to the latest version of
Community Server in the short term.  Who knows if I'll move to
WordPress MU in the future, but for now I'm going to stick with
Community Server.  The main problem was finding a replacement for the photo galleries.  Coppermine seemed like a decent alternative, but I'd really like something that allows me to have "local"
galleries as well as integrating 3rd party galleries like Flickr. 
Until I find something that solves that, I guess I'm stuck with
Community Server.