Though I’m not RTFirefly, here are my general responses.
USB–of course. Even the cheapest PCs have 4 to 6, including 2 up front.
Firewire–far less common. If you get it, it’ll be integrated on the motherboard. It might take off with more multimedia and the popularity of the iPod, but the average user doesn’t care about the difference between USB2 and 6-pin FireWire.
Graphics card–not at the bargain level. Any graphics will be onboard at that level. If someone wants better graphics, they can easily buy a card.
DVD/CD-RW drive–Yes. Just as likely, if you’re buying when Dell is having a deal is getting a DVD-R drive, though I can see why having the CD-RW capability is more useful as the media is cheaper and completely standardized.
Integrated wireless antenna–unneeded. Many people don’t go WiFi or network. If they are setting up a home network, they’ll know if they want to get one.
Audio line-in–of course. Either onboard the motherboard or as part of a seperate sound card. There will generally be a microphone in and a line-out as well.
Digital audio out–probably not, but once again, not used by a whole lot of people. I don’t think I have it (my sound card is nearly 5 years old, but I might have S/PDIF) but I’ve never had anything with which I could use it. Besides, if I need to use the analog hole, I need the audio line-in.
Footprint–I’ve never liked the total to near-total integration and lack of upgradability in today’s Macs, from the iMac to the G5. As a guy who homebrews and does hardware upgrades fairly often, I don’t like having my hands tied by something like an iMac. The G5 is basically a minitower, which doesn’t prove anything on the under-the-desk criticism. If you can fit the G5 tower on your desk, you can fit a small PC tower. As for the flat-panel, well flat-panel generally comes standard on most bargain computers, especially when someone is running a deal. Personally, I prefer a flat-screen CRT, especially for gaming, despite the size.
I’m not going to be switching any time soon. I have too much already tied up in software and hardware. I’m a homebrewer–I could build a system as good or better than the G5 for the same or less cost. 64-bit computing? AMD has 64-bit mobos and CPUs out there, and Microsoft just released XP-64. Dual-processing? I could find a mobo that could handle it, but I don’t need it by any means.
Look, you’re right that for the average user, a Mac is a perfectly fine choice. Even better, in some ways, especially if someone is afraid of doing anything to their computer or want to think of it as a toaster. But if you’re like me, you upgrade. A lot. You don’t go Linux for the same reason you don’t go Apple. You have hundreds of dollars already sunk into software that you want to keep using, as that saves money that can go to better hardware. You have hardware that you want to carry over, which can save money until you decide to upgrade the carried-over video or audio card. You know how to lock down a computer and how to keep it clean. Give me 2000 bucks and I’ll build an XP system using some of my current gear that will blow away a $2000 G5.