iTunes music for home and on the go?

How do folks manage your iTunes libraries so that you can have uncompressed files for the home rig and compressed files for the iPod? I've got 600+ CDs ripped (using Apple Lossless) on an external drive. What's the most sensible -- and easiest -- way to create compressed files to put some of this music on my iPod? (Assuming, that is, that that is the way to go.) Thanks.

-- Howard
Personally, I just used iTunes to compress the less, um, significant tunes in my collection. Then I left the stuff I really care about in Apple Lossless.

This got me under 113 GB, which to my memory is about how much an iPod Classic can hold (i.e., 120 GB minus the software, etc.).
Personally I wouldn't listen to compressed files even on my ipod. The ipods are pretty cheap nowdays for 120GB and storage is super cheap. Don't waste your time ripping files to MP3. There is a dullness to the sound that is audible on an ipod plugged into a car stereo and it's just not worth it.

I think you'd have to have another complete copy to reduce the file size, so you'd have to keep your original and then make another copy and reduce the size, then you'd have 2 qualities floating around in your itunes for your home system.
I rip all of my CD's to FLAC (lossless) format onto my Linux machine that is used by Squeezecenter for my Squeezeboxes. I wrote a program that creates MP3 files from the FLAC files in a parallel file tree, and this is run every night to seek out the new FLAC files that don't have MP3 equivalents. I point iTunes at these MP3 files. It took some effort, but it works like a charm now.

Ripped CDs that I wanted to FLAC and then moved them to iPod 120GB.

Cherry picked songs from iTunes (only high-quality music with 256-Kbps AAC encoding) and then synced to iPod.
If you use a mac, google Doug's scripts. You'll find a little program that compresses losless on the fly for your ipod, but keeps the original ones in AL.
Lapierre, Correct me if I am wrong but I don't think iPod supports FLAC.
It's fairly easy to keep two iTunes libraries, one with only lossless files and the other with mp3's. If you hold down the 'Option' key when you launch iTunes on the Mac, or the 'Shift' key in Windows, you will be asked to select which library you want to use or whether you want to create a new one. Once it launches you plug in the iPod you want to use with those files and sync. I keep the lossless library on my computer and the mp3 library on a small external drive but you could do it the other way around or even have them both on the same drive.

There may be easier ways to do this but when I rip a CD to Apple Lossless I then select all those files in the library window and choose the menu item 'Create MP3 version'. Then I quit iTunes, hold down the option key and launch the other library, then drag the mp3 files from the iTunes music folder (not the library window) into iTunes. It sounds more complicated that it is.

If you have a lot of lossless and mp3 files mixed together in your original library you can use Spotlight (on the Mac) to search by file type for all the .mp3 files, move them to another place for import into the mp3 library and use iTunes itself to delete the entries for them in the library by sorting your songs by 'Kind.'
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I transfer the apple lossless music files I want from my dedicated server to a portable external drive. Then I import them into my laptop using iTune. They are converted to mp3, then moved to my 8 gig ipod.
I go with a totally different solution. I do not need thousands of CDs on my iPod. Having access to them over time is great, but I don't listen to all my songs, artists, or even genres every day. I put everything in lossless and keep it in lossless. I then have a bunch of different playlists, or mini-libraries set up, and when I want to load different music onto my iPod, I just click a different set of playlists or albums, and it replaces them.
There is an application called Libra that manages multiple iTunes libraries for you. I use it for this, and other purposes.