playback, hard drive vs. transport/DAC

Thinking about building a PC for playing my 24bit recordings, and lots of redbook stuff as well.

Wondering how music comming off of a hard drive would compare to a good quality transport. ?
Any one?

things like this intriege me.
If done right,You'll be blown away! The industry will never support hard disk play back. It takes sells from away from transports,DACs,and preamps. A good PC based playback will replace all these products and give you much better peformance and will leave you plenty of change left over.
Honestly, with all of the junk/noise inside a pc, do you think that you can isolate the drive, power supply, d/a and more enough to really make it worth while. Why do you think that they make transports with seperate power supplies and DAC's. They do it to isolate each function to improve clarity and purity of signal.
I've ripped apart many a PC and can't imagine how much static, dust and noise from the cooling fan occur. Plus, with the PC hooked up to a phone line/dsl/printer/monitor it would simply make it that much harder to isolate audio without any interference.
Finally, with the drive and dac sharing the powersupply with everything else, you will have a hard time keeping the signal clean.
I see the hard disk based solutions replacing dedicated transports, but not DACs. In fact, I see hard disks and outboard DACs complimenting each other rather nicely. :-)