At any rate, one of my first posts mentioned an open-source project called, generically-enough, Ps3 Media Server. Back then, it appeared that the software worked, but didn't make the cut for me because it was a cross-platform solution (written in Java) that did not have any support for my iTunes playlists. I didn't really want to serve up my 6000 MP3 in a big jumble - I've worked a bunch on my playlists and wanted to use them over on the PS3.
Well, I've taken another look and over on the code site for PS3MS (or whatever it's abbreviated to), and they now have a Mac OS X-specific build that adds a couple of key options for sharing not only your iTunes library, but also your iPhoto library automatically. And I can report - it works well. iPhoto events and albums both show up correctly, with thumbnails. And the entire iTunes library, with playlists, artists, genres, etc. all show up as appropriate under both the music and video entries on the XMB.
There's even some support for streaming content from the web (YouTube and such), although I'm not able to get most of it to work myself. Maybe I need to twiddle around with the transcoder settings. I'm using a slightly older version (the latest builds are listed as Intel-only, and I'm still running on an old G5), so maybe there are issues that have been resolved by now. Don't know if the elusive Hulu is available through this thing or not (although I don't see how you would do any searching with this interface yet).
So, I'm giving this an extended shot. So far it's worked well....except that I do get some network issues still (with an error code of 80710736) during video playback. I haven't tried a wired connection to see if this resolves the problem or not yet, but I probably will at some point. At any rate, Mac-to-PS3 users may want to give the OS X-specific build a look.