QUOTE (swayzak @ Apr 4 2008, 01:32)

I've downloaded almost all my music as mp3 (mostly Lame extreme ie, VBR approx. 230 kbit).
At the time I wasn't really au fait with other "better" formats such as FLAC & Ogg Vorbis.
Is the quality massively different (both on portable player/car stereo & home listening) ?
I guess you meant "ripped and encoded". No, you haven't made a big mistake.
At that bitrate it really won't make much difference what you used. Previous listening tests have shown that most people can't tell the difference between an encoding made with
any reasonable codec and the CD at bitrates above 128kbps. If you wanted to you could look through the results of some listening tests, some of which were conducted by people at this forum, here:
http://en.wikipedia.org/wiki/Codec_listening_testSo nothing to worry about. The advantage of more up-to-date lossy codecs like Ogg Vorbis and AAC is that they will, on the whole, sound better if you use very
low bitrates -- which some people need to do for various reasons, such as having portable players with limited hard-drive space. But you used a high bitrate, anyway, so that's not applicable to you. And there is still an advantage of your having used LAME in that MP3 is still the most widely compatible codec when it comes to players and devices.
FLAC is a different matter. That is a
lossless codec. People tend to use that for making bit-perfect copies of their CDs in case their CDs get lost or damaged rather than for actually listening to. It can also be nice to store one's music like that and transcode it to whatever lossy format one wants for any particular purpose at any particular time -- low-to-medium bitrate MP4 for an iPod, MP3 for burning an MP3 CD for playing in the car, Ogg Vorbis for playing on a Linux machine that hasn't, by default, got the software to decode MP3s owing to licensing conditions, and so on ... It's quicker and easier than re-ripping and re-encoding.
But for listening purposes -- well, you're very unlikely to be able to hear the difference between LAME VBR at ~230kbps and a FLAC file on almost any sample you might try.