All of my shared music is done in wav format, I can record at 196kbs which gives me a 96KHz response. The sound card cannot reproduce this. The Sound card I Have cuts off at approx. 22KHz, which is more than enough for high quality CD's. The major part of my music is from LP's that are over 50 years old and they are higher quality then any CD. I have albulms that have a frequency response of over 28KHz.
Enough retoric now the facts.

If you are using an mp3 player that you carry around with you 128Kbps is adequate. If your computer is hooked up to your sound system, which mine is. The sylstem itself consists of an Altec Lansing, and a Mixture of JBL woofer and an Altec Lansing 800Hz horn and driver, amplifier is irrelivant but it's a Sony. This system will demonstrate the lack of qualitly in mp3's even at 320Kbs.

Again, you!! have to decide what is adiquate for you.

As far as sharing I share the highest quality I can, although I might put it out as an mp4 ie AAC, this is what Nero uses for there highest quality.

Once you download a wav or mp4, flacc, ogg vqf ect. these can be converted to an mp3 using Nero.

Open Nero "Smart Start" go to Nero Burning Rom, the "New compilation" screen click on "cancel " then go to Extras (F8) and then go to encoded and pick the format you wish.

I SURE HOPE THIS MAKES SENSE.