[bigshot]

ogg is pretty close to AAC. I think it's MP4, right? Generally, I find that AAC is the same as MP3 LAME one notch up, and two notches on Frauenhofer. So Frauenhofer MP3 320 is the same as LAME 256 or AAC/Ogg 192. All of those are transparent in 99.9% of music. In my library, I've gone one notch into overkill... AAC 256. I added VBR so the file would be distributed intelligently. 

 

[xnor]

Vorbis and AAC are the codecs / formats that contain the audio, Ogg and mp4 the containers (for example for tags).
 
Vorbis VBR@200 should be a bit better than MP3 V0, so transparent in virtually every case.

 

[carltonh]

I'm going to zombie to life an old thread. But I have been unable to tell a difference from my flac files vs. ogg and 256 kbps+ mp3. If I love an album and buy the CD, I'll encode albums I love most and own on CD in FLAC. If not as much, I'll choose somewhere between 256 and 500 kbps OGG. If I buy a digital album in MP3, I don't convert it.