I use Audiograbber with LAME codec.
I use VBR on setting 4, which gives MP3s typically around 192 average bitrate, but assigns quiet parts lower bitrate and complex parts a higher bitrate. I have some songs as high as 210 kbps, some as low as 67.
MP3s should ALL be VBR as far as I'm concerned, since it makes NO sense giving silence 320 kbps!!!