Also its important to know that the bass, mids and highs are cut so that the music is not as "transparent" in 192 kbps as on cd. I know this after Djing. I used to use mp3s and argued that the sound was the same, but now I only use cd and wavs in 44.1 stereo.
Sometimes you can see the difference in winamp(or any visual eq after encoding). Sometimes it looks even more loud aswell(according to the peaks in the visual eq. But remember when the frequencies are cut, they are cut!
If you want premium compressed files i would go for the AAC(if you can play it though) It has the best compression rates and sounds better(for me).
Also remember to not use joint stereo while decoding! It makes the stereo image too narrow(atleast for me). If you want a decent sounding mp3 I would go VBR settings at 192-320 kbps full stereo.
That will give a better file size and better sounding mp3s