The much awaited results of the Public, Multiformat Listening Test @ 48 kbps are ready.
Here is the results page: http://www.maresweb.de/listening-tests/mf-48-1/results.htm
Nero is first, followed by Vorbis and WMA Pro. which are tied on second place, WMA Standard is third and loses.
I think this test shows that with modern encoders, the quality at 48 kbps is acceptable and should be good enough for Internet streaming or portable use with cell phones for example. It's also interesting to see that WMA Professional perfomed quite well although it was the only contender that used CBR.