I recently went through a similar process. I believe the sound quality has more to do with the bit rate that you rip than the hardware since you aren't doing any analog conversion in the process. I wanted to rip in lossless but with 620 CD's the library would have been huge so I settled on 296 which sounds good on my current system. With the way storage space is going higher and higher I'm sure in a few years I'll be able to go back and rip everything again in a lossless format.

That's awfully industrious of you! I had to rip about 100 CDs, and it took me a day. They're all Apple Lossless. I also just bought an external drive and I'm currently copying my entire library (about 115 GB) to it. I have capacity, but I wish I had the extra money for redundancy. If this puppy goes down, it's all gone. Yikes.