I've been doing some reading online about mp3 quality and settings and it seems as though I might need to redo my collection.I used Audiograbber using the lame internal encoder with settings of CBR320, high quality,joint stereo.Most people recommend using the external encoder settings and various command lines such as --alt-preset standard,--alt-preset extreme and --alt-preset insane. So my question is are there better settings than the ones I used or am I ok with what I had.Keep in mind that I'd like the highest sound quality MP3 file (otherwise I guess i'd just use a wav file)
Comments suggestions appreciated

It's all up to the individual, I personally consider myself somewhere between the average listener and a "golden ear" audiophile, so alt-preset-standard is fine for me, and I can only personally hear artifacts in a 128kbps CBR file on a really good system. The rule of thumb is if you can do a blind listening test and not hear the difference, then pick the smaller file. You're not going to impress anyone by having a higher bitrate, but you'll be very happy to fit more music on your empeg. Or that's the way I look at it, anyway. When I did my own blind listening tests, I found I could tell a 128k versus an alt-preset-standard a little better than 70% of the time, so I went with that. But a lot of times, in my car especially, I really wouldn't be able to tell.

320kps is the highest rate that mp3s can encode at (and as Tony said, higher than needed for most people.) Any VBR file (which the alt presets are) is going to use rates 320 and below depending on the complexity of the song. Alt preset Insane nearly is a 320CBR file because of the % of it's frames that end up using 320kps. Personally, I think that is over kill.

The only reason I can see recommending the external encoder is because there are other settings built into it besides bit rate such as frequency roll off etc.

FWIW, the guys that put together LAME use alt preset standard.

If your concern is archiving, I'd recommend ripping to FLAC for storing your files, then convert to mp3 Alt Preset Standard for your mp3 players or Ogg Vorbis, etc, whatver the flavor of the year is. FLAC is a lossless format great for archiving.

Remember that the larger the bitrate, the more frequently the disks need to spin up. It's not worth going beyoun alt-preset-standard IMO.

I used Audiograbber using the lame internal encoder with settings of CBR320, high quality,joint stereo.

That's the highest it will go, isn't it?

I believe that if you re-encode your collection, you'll be wasting your time. I don't think anyone, even golden-eared types, will be able to tell the difference between what you've got now and what you're thinking of doing.

Ok,so for future encodes I should just use the Alt Preset Standard setting.However the only way I can choose this is to use the external encoder.If I use the internal decoder I Guess I would choose VBR high quality and the encoder will decide on the bitrate depending on the song itself?Possibly as high as 320 or as low as 128? I guess I'll have to try it both ways and hear if I can hear the difference.