CBR 320 (highest possible LAME quality):
--alt-preset insane
(bitrate: 320 kbit)

VBR (variable bitrate) settings:
Very High Quality +
--alt-preset extreme
(bitrates 220-270 kbit/s -- usually averages around 256kbps)

Faster (Very Slightly Lower Quality):
--alt-preset fast extreme
(bitrates roughly the same as above)

Very High Quality
--alt-preset standard
(bitrates 180-220 kbit/s -- usually averages around 192 kbps)

Faster, slightly lower quality possible:
--alt-preset fast standard
(bitrates roughly the same as above)

High Quality
(Due to the new "--alt-preset standard", the "--r3mix" setting is obsolete.)
--r3mix
(average bitrate ~190kbit/s (150-230kbit/s)

ABR (average bitrate) settings: (128 kbit ABR: roughly the same filesize as 128 kbit CBR)
ABR Setting tuned from 320 kbps down to 80 kbps

--alt-preset <bitrate>
Example:
--alt-preset 200

ABR averaging at 128 kbit/s
--alt-preset 128

or (see http://www.ff123.net/cbr128.html ):
--abr 128 -h --nspsytune --athtype 2 --lowpass 16 --ns-bass -8 --scale 0.93

CBR (constant bitrate) settings:
320 kbit/s CBR
Highest Lame Quality:
--alt-preset insane
or
--alt-preset cbr 320

256 kbit/s CBR
--alt-preset cbr 256

192 kbit/s CBR
--alt-preset cbr 192

160 kbit/s CBR
--alt-preset cbr 160

128 kbit/s CBR
--alt-preset cbr 128

or (see http://www.ff123.net/cbr128.html ):
-h --nspsytune --athtype 2 --lowpass 16 --ns-bass -8 --scale 0.93

96 kbit/s CBR
--alt-preset cbr 96

80 kbit/s CBR
--alt-preset cbr 80