So far the largest commercially available silicon drives are only 320GB, which may be too small for the largest computer music libraries. But for many users 320GB silicon drives make an excellent choice for storing music files. On my Dell D620, for example, I have the option to use a standard internal drive for my operating system while storing my music files on a silicon drive mounted in a removable drive sled that goes into the slot that normally holds a CD-ROM drive. This rig makes a fine portable and completely self-contained music server.
Even the most conservative and untweaky audiophile should realize that for better or worse, cables have an audible effect on sound. Just because a music system is computer-based doesn't mean that cabling will suddenly be any less important than in a conventional system. Unfortunately many owners of computer-based systems put little energy or resources into their cable options. Regardless of whether you employ USB or FireWire between your computer and other external sound devices, I would recommend never using the free cables that come with your external hard drives. The least expensive cables I use are the Belkin Gold Series USB and FireWire cables. In my computer audio system I've been using the Belkin Gold USB cables with excellent results. A serious step up from the Belkin Gold is the Locus Designs Polestar cable. In almost every setup where I've substituted the Polestar for the Belkin Gold I've found the Polestar delivers a noticeable sonic improvement.
Many computers use standard IEC AC cable connections. Experimenting with higher-grade AC cables can have beneficial sonic results. Just as with conventional audio components an AC cable that delivers superior filtering and/or isolation capabilities can improve the overall sound of a computer-based system. [The sound of my PC-based server improved noticeably after replacing the stock AC power cord with a mid-priced cord from Shunyata.--RH]
Never plug a computer directly into your AC wall outlets. Computers are highly sensitive to all forms of AC power anomalies--surges, brownouts, sudden power losses can all wreak havoc on a computer's sensitive circuitry. Computers need to have at least a UPS (uninterruptable power supply) unit with spike protection so that if you have a power problem your computer won't shut down mid-operation, leading to corrupted files. If you do suddenly lose AC power, it's important to have the opportunity to shut down a computer correctly to avoid future problems.
In a computer-based audio system you should also try to isolate your computer's AC from the rest of your system. That's because a computer's power supplies can have an audible negative effect on the rest of your audio system. I recommend keeping your computer on an entirely different circuit if possible. If that's not feasible, isolating your audio components from your computer with a brickwall power protection/conditioning system such as the PS Audio PowerPlant Premier will prevent the digital switching power supplies in the computer from dumping noise into the rest of your system. My own AC power line tests have shown that my Dual Core Xeon PowerMac does produce some AC noise. Currently I use AudioQuest NRG-3 AC power cables for all the audio components in my system connected to a PS Audio Quartet power conditioner to isolate them from my Mac's AC power noise.
You can find a plethora of conflicting information on which method is best for connecting your computer to an outboard DAC. Advocates of FireWire argue that since it's been the professional standard for a number of years, it's also the best option for high-end consumer-audio setups. USB proponents point to the ubiquity of USB and the ease of setup. Coaxial boosters write about coaxial connections having the lowest inherent jitter rates. Finally, TosLink fans point to the complete galvanic isolation between computer and the rest of your audio chain that only TosLink offers. So what's an audiophile to do?
All of the points made in the paragraph above are valid. And, frankly, there is no clear-cut universally sonically superior method for connecting your computer to a DAC. In every system other variables, such as your software and hardware choices, will make a profound difference in which method is sonically the most advantageous. Also the only way to know which will work best is by trying each connection and listening to the results. Alan Taffel found in the systems he tested that coaxial and FireWire were optimal. I've found that in some configurations TosLink or USB produced the best results. My advice is to try all your options and don't make any final decisions until you've finished listening critically. The old cliché, "Your mileage may vary," was never more appropriate.