A couple of points:
As long as you have a home ethernet or 802.11 (wifi) network up and running, the Slim Devices/Logitech devices can be addressed by the Squeeze Box Server (the player) and as has been pointed out, it doesn't necessarily need to be loaded onto a PC. The music files can be located elsewhere as well.
One thing that I have found is that by running this system in a wired configuration, the WiFi card on the SB devices can be powered off during configuration and the electrical noise that the card generated is saved. This also results in a nice improvement in sound quality. The elimination of the wall wart SMPS by replacing it w/ linear, regulated PS is IMO the largest single improvement. Its not a subtle improvement but the official line over on the Slim Devices forum is to deny this rather obvious fact.
During the ripping process, access to the internet allows Exact Audio Copy or dBpoweramp, access to several online databases like freeDb and AccurateRip, to compare with to check the accuracy of your ripped music files. I prefer to rip to flac as its native in Slim Devices and allows easy metadata tagging for use down the line, when you may need to move these files around.
The Transporter's biggest advantage over the less expensive SB products, is its ability to decode HiDef formats up to 24/96. The upcoming Touch will also allow this resolution at a bargain price.
I personally only have Red Book rips @16/44.1 but w/ Hidef files becoming more common, I will eventually have to upgrade.
I also believe that just about everything affects sound quality. I also have my SB3s' digital outputs significantly. modded. Reports of the Touch beta tests are that its SPDIF output is excellent in stock trim, if it ever goes on sale. While there is a mini version of the player software onboard the Touch, I still believe that getting the mechanical and electrical noise of a HDD away from the listening environment is a better solution. SS drives, while quiet are too expensive and small to be a consideration yet.