How do I know if iTunes files are all 'lossless'?

Denf,

The key is the import settings in itunes need to be set to AIFF, or WAV to get the best sound using itunes. As noted, this will make good sounding files when you import by ripping CDs. After you buy a crappy file from itunes store, it is AND ALWAYS WILL BE a crappy file. Itunes will let you convert it to AIFF later, but the data you want isn't there. It's sorta like magnifying a crappy photocopy, it's too late.
HDtracks and most other good format downloadable stuff is FLAC, so itunes can't read it. If you only use ipods or stuff that can work with itunes (e.g. Squeezebox for home rig) you can just convert FLAC into AIFF with separate piece of software(search FLAC to itunes). For me, the problem is that I also have a Cowon J3 portable that only plays FLAC, so I am stuck for now with two libraries, one in AIFF and one in FLAC. A PITA for sure! Cheers,
Spencer

Does anyone here use any 3rd party plugins to itunes that allow native FLAC in itunes? Cheers,

Spencer

Spiritualized, I hear ya, but I don't want to convert to AIFF, as my portable can only play FLAC. I want to get FLAC files from hdtracks.com and keep them FLAC, but manage only one library. Any ideas? Cheers,
Spencer