USB-S/PDIF Converter or USB DAC?

I've decided it's time to use a music server with my main system. I currently use one (iBook) with my headphone system with the Grace m902 headphone amp with built-in USB DAC. I intend to get a new Intel iBook when they are released (March/April).

I currently have an unused Wavelength Audio S/PDIF DAC that I could use with a USB-S/PDIF converter (such as Empirical or Red Wine Audio) or get a USB DAC (WA Brick, Stello, ???). Is a dedicated USB DAC preferred over the hack USB-S/PDIF converter route?
Budrew, you are heading in the right direction. YES! USB has many advantages over SPDIF. One big advantage is that USB is bidiretional in it's signal transfer. The signal is error corrected at both input and output, resulting in a bit for bit transfer of data. Not to mention the added benefit of having an exact bit for bit copy of your all your CDs at your fingertips. Just don't forget to back-up your data.
Budrew -- I have the Wavelength Cosecant (after trading up from the Brick), and have to second Terrat's observations. Both are the best digital I've ever heard, and while the Cosecant is significantly better than the Brick, I'd have to say the latter is more of a bargain. (Both are basically the same USB DAC design, but the Cosecant has an output transformer and a better power supply).

I have no experience with other USB DAC's. I'm fairly sure that a lot depends on how well the USB controller is implemented and how good the actual DAC part is. For example, Gordon Rankin uses no up or oversampling. I don't say this because it is necessarily better or worse, just to indicate that different USB DAC's are likely to sound different, like everywhere else in audio. Make sure you buy something that sounds good to you in reality, not just in concept. End of lecture ;<) Hope that helps. -- David
Thanks, I'm going the USB DAC route. I actually had an early Cosecant, but did not use it much at the time so I sold it. But now computer audio is really useful for me and I like the character of Gordon's DACs. I'll probably spring for the Cosecant.
Budrew -- fyi, since you sold your Cosecant, he's come out with a new version -- same guts, but he tweaked the cosmetics -- check his web site. -- David