for a mark of a good quality mp3 is it the bit rate you have to look for?
obviously 96kbps is the worst and I believe it peaks at 320, myspace rips are generally at 96 because mr murdoch likes to save his pennies by compressing uploads from bands
any other tips re knowing quality of mp3s would be welcomed :)

vbr (variable bit rate) v0
is SUPPOSEDLY better than 320kbps, although i don't like the idea of a computer deciding what bits of songs require a higher kbp level
it also depends on the file format and the encoder - AAC is thought to be the better of the most well known ones with mp3 a bit worse, whilst the LAME encoder is supposed to be the best
cheers
for this :)
i prefer stuff to be at least 192kbps
because that is about the threshold at which i find quality can be called 'good'. 320k is audibly superior though (bear in mind cds are about 1200k or something similar) also it will vary to peoples ear and on what system you listen to it. put it this way, i wouldn't download anything less than 192k, and i rip cds at 320.
Yeah, use V0
They have the best file size to "good sound" ratio in MP3s I think. Apparently V2 is almost indistinguishable too, but I go with V0's just to be safe, especially if you're listening on better than average equipment. Encode them using LAME too :) theres lots of ways mp3s can be encode but some of them (xing, FhG, Blade) are outdated and one of these in a high bitrate may not sound as good as a lower bitrate LAME, if you get me?
Regarding myspace mp3s, a few years ago myspace used to let you download the songs at whatever bitrate they were uploaded in (if you pressed the download link, not captured the stream). When it got a bit more popular they changed this to 96kbps. I think they've changed it back again to higher now though, although I'm not sure. :)