What's your favorite audio codec?

I like this idea a lot but it poses two problems in my mind: you need A LOT of storage on your computer (I just have a mac laptop, I'd have to buy a huge external drive) and you have to spend time putting all of your music into two formats. Do you have a way to speed this up? How do you boot two libraries with iTunes?

When you say huge, how huge? How many gigs of music in total do you have?

To boot to a different library, hold shift then click iTunes while holding shift, you will be prompted to either choose or create a new library. iTunes (2) is the default I believe.

And yes, you would have to spend time putting music into two formats and then manage two libraries as well. I personally find it to be totally worth the (small) effort for my needs of both portable and hi-end home audio. I personally wouldn't dare put an MP3 (AAC) near my home system, and feel it is wasteful to put lossless on my wifes' IPod (she is the primary user of the portable audio). So this method allows me more control over my entire collection. All you have to is burn everything in Lossless and then have iTunes downgrade the other library to AAC. You can always take away data, just can't ad-which I am sure you are aware of.

But in the end, you have to have the space for it.

If I hadn't already ripped 15 GB of music into lossy, I'd take your advice Jc51373! I like your solution.