Best bitrate for online streaming (aka internet radio). Options

[uart]

I know that for most of us, as storage capacities have increased we've generally become less concerned about being economic with the bit rates of our encoded music formats. One area however where I"m still kinda interested in bit rate economy is when listening to internet streamed music such as "internet radio". The reason is simple, I've only got 10GB/month downloads and I'd prefer to not use more than about 30% of this for online listening, particularly as it's something that I'm often just using as "background" music.

With that said, what bit-rates to others here find suitable for online radio purposes. Personally I seem to find 64 kbps HE-AAC to be roughly equivalent to FM radio, though that's only a subjective judgement. Just wondering if anyone knew of any tests to establish what codec/bitrates are roughly equivalent FM radio for typical music listening purposes?

Thanks.

[Brazil2]

Many available formats and bitrates at Absolute Radio stations, I've selected two of them which offer a wide variety of styles from funk to metal:
http://absolute80s.com/listen/other/
http://absoluteclassicrock.co.uk/listen/other/

They are also using MP3@192 kbps and HE-AAC@64 kbps if you register to the site... or use Google

[Stone Free]

Many available formats and bitrates at Absolute Radio stations, I've selected two of them which offer a wide variety of styles from funk to metal:
http://absolute80s.com/listen/other/
http://absoluteclassicrock.co.uk/listen/other/

They are also using MP3@192 kbps and HE-AAC@64 kbps if you register to the site... or use Google

CODE

Windows Media Player 20k:
Windows Media Player 132k:

AAC+ 48k:
MP3 32k:
MP3 128k:
Quicktime 32k:
Ogg Vorbis 32k:
Ogg Vorbis ~160k:
Ogg FLAC ~1Mb:

Can someone rank these? Or should I assume that on the whole they are already in increasing order of quality, apart from the first one, not sure where that one fits.

Also where is the info on MP3192, and AAC64, for absoluteradio?

[Brazil2]

Also where is the info on MP3192, and AAC64, for absoluteradio?

http://www.absoluteradio.co.uk/listen/on-other-devices.html

Direct links:

Absolute 80s HE-AAC 64kbps:
http://aacplus-a8-64.as34763.net

Absolute 80s MP3 192kbps:
http://mp3-a8-192.as34763.net

Absolute 80s Vorbis 160kbps:
http://ogg2.as34763.net/a8160.ogg

Absolute Classic Rock HE-AAC 64kbps:
http://aacplus-ac-64.as34763.net

Absolute Classic Rock MP3 192kbps:
http://mp3-ac-192.as34763.net

Absolute Classic Rock Vorbis 160kbps:
http://ogg2.as34763.net/vc160.ogg