I have 1500 cds

I am no expert in and haven't done it myself so I hope others chime in.
It's file type in this case it is considered one of the more exact,well,a virtually exact copy of the digital data it is given. CD-W is simply a ripped copy I was thinking of records when I read this.
I have heard that a WAV file is one of the better files if not the best. Lossless I think was initially for Apple computers, i-pods etc, but now available for other platforms .ie. Windows

Lossless = Apple Lossless and FLAC (free lossless audio codec). They both maintain 100% of the information whereas mp3s and AAC files trim data to make the files smaller. Apple lossless and FLAC store the data in a compressed format and the software uncompresses it as it is played.

WAV and AIFF files are uncompressed Lossless files. Many people, including me, find that they sound better than apple lossless and flac. They also take about 2-3x the space, so usually about 50-60mb per song. I'd get 2 terabytes and rip them in AIFF.

Lossless is lossless. Any difference in sound quality is due to a mistake upstream.

Flac, ape, and alac (apple lossless) compress around 50%.

I use a squeezebox to lift the bits off the computer and then you get two choices: straight to DAC (best) and using the SB's own DAC, go with RCA interconnects into a preamp (or even an amp or powered speakers if you don't care about hifi).

The squeezebox interprets FLAC natively, the rest get converted on the fly (usually OK but it makes your computer system work harder).

I went with FLAC because it is an open standard and, twenty centuries from now, it should still be OK. :) Apple, otoh, can change its corporate mind tomorrow and then you may have to scramble a little bit (e.g., somewhere around v. 4, iTunes stopped reading flac files for no good reason and they've been bloody corposilent about why they did that).

Naturally, such concerns are amplified by a large integer when you let Bill Gates' outfit handle your file formats.

Ape is also somewhat open but not really. So the overwhelming majority of people have gone with flac, if they think about it at all (naturally, not if they just download from the Apple store!).

Whatever format you choose, you'll notice it is a lot easier to shuffle through your collection than having to get the plastic discs off your shelves.

It will take you a long time to rip that many CD's, I have done a collection of 700 discs twice as I initially ripped them in as MP3's, then went back and re-did it in AIFF, both times it took a month or more of spare time, so by my rate, 1,500 will likely take two months, whatever and however you opt to do it (I would recommend doing it in lossless or raw (AIFF/WAV) files) make sure you back up the library frequently.

I suggest doing it totally uncompressed/raw as storage is cheap (TB drives are easily had for <$80) and you can always compress them to anything you want, MP3/AAC at any bitrate down the road, while maintaining the originals. You can't make uncompressed out of MP3/AAC (well, you could but you already lost data, and can't ever get it back, whereas if you start with some form of raw or lossless coding, you always have the native CD data on your drive.....