Optimal encoding for MP3 files

I have a 160 GB iPod that has only about 50GB used thus far with 128kbps CBR MP3 files. They are automatically created from FLAC files. So what I'm contemplating is rebuilding all of the MP3 files in a higher-quality format. That will take about 5 minutes of programming time and a month or two of computer time.

Here are some options:

MP3 VBR with 192k floor (lame -v -V 2 -b 192)
MP3 CBR at 256K (lame -h --cbr -b 256)
MP3 CBR at 192k (lame -h --cbr -b 192)

I'll experiment to determine size vs sound quality, but was wondering if anyone already investigated different MP3 encoding options and could weight in.

I have read time and time again that 192 VBR was the best compromise between sound quality and compressed size. I have listened to 192 VBRs and they do sound quite good.

However, if you can afford a bit of additional disc space, you might want to consider going with 256 VBR.

I recommend to take a few of your best-known, best-loved recordings and experiment with these two encoding schemes. Let *your* ears decide...

I like RW's suggestion. It's great if you can enjoy the smaller files.

I discovered I wasn't interested in listening to music (as opposed to spoken word) on my iPod unless the files were 16/44 lossless and the interface was a SendStation line out dock and a portable headphone amp. That was after trying 128 KB, 192 KB and 320 KB VBR MP3s. ( I did not rip 50GB of files four times, though. :P )

The 256 and 320 versions were OK but... over time I just found I wasn't very interested. So what I do now is cycle old music off and new music onto the iPod when space gets tight and I want a change.