Hi mega_mike,
I was lamenting the same myself for a few weeks and through trial-and-error have found the easiest and by far the most reliable to be Samba. I have a Fedora 12 machine running Samba with Share Level security and it’s worked great. Streaming HD .mkv files without missing a beat. I have the Fedora machine wired to my router, then the WD TV Live running over wireless with a D-Link DWA-140. Everything else I tried was just too complicated - Samba was 5 minutes work to set up and use.
To be honest, I was shocked at how well it actually worked!
I hope this of some use to you - good luck!
