...could I then take that hard drive and plug it into my htpc...

Yes, you could.

When ripping audio CDs keep in mind that mathematically lossless codecs can cut WAV sizes in half.
Perceptually lossless cut it in half one more time.

 

What you want to do will work just fine. In fact, that's a very common usage - ripping CDs to make them portable to IPods, Media Servers, other PCs, etc.

 

... if I ripped all my cd's using my laptop onto a portable hard drive could I then take that hard drive and plug it into my htpc ... or do they need the original computer to work?

Unlike some (most?) legally-downloaded music, audio files created from CDs are not tied by "digital keys" to the device to which they have been ripped, so they can be moved at will to any other device.

 

Thanks folks for your replies.....I never thought about it but I guess it is just like putting your music on an IPOD or other portable device and playing it anywhere

thanks again