Spent all night last night playing with the hacker edition of 07. So far extremely happy, the OS is MUCH more stable than 2006 for me; browser is faster, programs don't crash as often, my wireless automatically connects on bootup. My only gripe is the built-in audio player refuses to play mp3 files. From what I read in the wiki, mp3 support was left out due to copyright issues...

So my question is, what are you guys using to play your audio files on the hacker edition?

hm? I can play mp3 on my Nokia 770 and the OS2007 Hacker Edition.
You don't have the codes from the N800, but you have still the ones from the N770.
So mp3 is definitly working.
But i think you have to "activate" it. Please look at the buglist on https://garage.maemo.org/projects/os2007on770/