Chris, I dove into the computer/internet-based music world recently and beliieve my experience can possibly provide some more insight for you. I basically had the same criteria as you did, including multi-room access, one-spot storage of music, high-quality sound, etc. I elected to stay away from the USB route as it is my understanding that: (1) the DAC has to be hard-wired to the computer in this configuration and (2) it also requires a computer to be on to play music.
I decided to go wireless and purchased: (1) a Slim Devices Transporter and (2) a NetGear ReadyNAS (Network Array Server) configured for SlimServer and with 3 TB of raw storage. Since I have configured the NAS with x-RAID (Redundant Array of Inexpensive Disks) for automatic data back-ups, my effective storage capacity is ~1.85 TB, or some 5,000 CDs +/- when ripped in FLAC (Free Lossless Audio Codec). I chose FLAC since: (1) I have a PC and not a Mac, (2) FLAC saves disk space and transmission bandwidth, (3) is "bit-perfect" lossless, (4) the Slim Devices have FLAC firmware for data decompression, and, probably most importantly, (5) FLAC incorporates tags with meta-data (e.g., album, artist, track, etc.) for each file/song whereas this information is lacking with WAV files (note: tags are important for sorting an album's songs correctly instead of alphabetically and for managing large databases of albums/songs).
Of course, FLAC is not iPOD friendly - I don't think iPODs support FLAC, but you can easily substitute Apple Lossless for FLAC, or you could easily convert FLAC to any number of other codecs using readily available software.
The NAS installs as an IP address on the computer network. The Transporter gets digital data from the NAS wirelessly over the network without the computer being on; you can also connect the Transporter to the network using ethernet if you can/want to run cables. The Transporter also has the ability to turn the NAS on and off and can access internet radio via the network (again, without the PC on).
I also put a Slim Devices SqueezeBox 3 in another room and both the SB3 and Transporter can play eiher internet radio and/or any of the ripped files on the NAS at the same time. My understanding is that just about any number of SB3's or Transporters can all access the one NAS and/or internet simultaniously since they all install on the network using different IP addresses.
Both the SB3 and Transporter sound incredible, although the Transporter does sound more detailed and less grainy than the SB3. FWIW, I'm playing the Transporter through a PS Audio GCC amp and Duevel Bella Luna speakers. I also did some back-to-back comparisons between the music off the Transporter versus playing the original CD on my well-used Underwood HiFi Level 2 modded Jolida JD100A CDP. It really was a toss-up with both having great detail and soundstage, but the Jolida had the edge with "warmth" IMHO, which I attributed to the vacuum stage output.
The total cost for this leap into the computer/internet-based music world was about $3,600, with $1,700 for the Transporter and another $1,900 for the NAS. You can save money on the NAS by specifying lower capacity hard drives, but I am also looking to use some of my extra storage for video.
Finally, as I am a fan of vacuum stage outputs, I will be shortly sending my Transporter into ModWright for their Class A "truth" mods. BTW - if you already have a high end DAC that you like, you can use the relatively cheap SB3 (only $300) to pass digital data to your high-end DAC.
Obviously, my opinion regarding the Transporter and Slim Devices technology is somewhat biased. Nevertheless, I am VERY pleased and suggest you give the SD technology a good look (or listen if you can). Good luck.
