Depends. What I don't like about using PCs as my source is that 1) it takes too long to start up, 2) errors from the other applications can get it in the way, and 3) I got tired of shifting settings - one for listening and no audio for alerts and another one with them. BUT, consider the following:
1. CD Players - outlived other attempts at high-res formats, and for paid music, CDs aren't doing that badly next to iTunes. The new trend now is to open the DAC circuit to other inputs, such as plain SPDIF, USB, even as an iDevice dock (or a slide-out dock, as in the Tascams.) The one place I can see it being outdated in no time is car audio: CDs skip more than HDDs, and SSDs will get cheaper. Not to mention it's easier to program voice commands to switch to other tracks or albums than fiddle with optical discs: eject, return to case, pull out other disc, insert.
2. TT's - they said analog was dead, then sales of both LPs and TTs jumped a few years ago, at the time that people were reacting to me with a, "who the hell still uses CDs?!"Same way a lot of people are into hybrids but some people will keep those V8 Camaros, Straight-6 BMW's and Jaguars, V12 Ferraris, Flat-6 Porsches running off dead dinosaurs for as long we can get dead dinosaurs.
3. iPod - Remember how the CD almost killed LPs (well it definitely killed the tape), then the iPod looked like it'll deal the deathblow to LPs, and looked like CDs too after it for the most part killed the MiniDisc? TT's are alive and so are CDs. Apple may have killed the iPod because people want multi-tasking iOS and Android devices, especially smartphones more than just touchscreen media players that can surf the web, but if the continued existence of the CD and TT are any indication, there is still a market for pure music players. Especially high-capacity lossless players: Ibasso DX100 coming soon.
4. PC with DAC - It won't totally replace the other systems soon enough. I mean, especially with "green consciousness" and all, why run a 4gb quad core liquid-cooled rig if you're just listening to music? When iDevice+digital docks become more affordable audiophiles might jump back on those and have them next to the PC. Imagine the convenience of scrolling on a FLAC-player equipped iPad 64gb on a Pure i20. Or, better, when more Android devices can do this without the need for a dock, and have an expansion SD slot to boot.
The one source unit that might potentially rule in the future, at least for pure audio enthusiasts? Music servers. No, not the network controllers like the new Musical Fidelity, I mean like the Olive HDD media players. Sure, there are lots of cheap media players floating around, but they were made for HT, and here are the problems for pure audio use:
1) They assume you have a flat screen for your HT, otherwise you either put these in the same room as the HT or the computer; or you upgrade your computer monitor and use the smalelr one with it.
2) Only digital outputs, so you can't just replace that Meridian with a dead transport, you have to buy a DAC, too.
The Olive did away with these problems by basically designing a CDPlayer, one model complete with a headphone amp, and either they replaced the transport with an HDD or they paired both in the same box. They're cheaper than Wadias of course but still expensive; but just imagine the time when NAD and Wadia realize at some point in the future that even the retirees in their target market are highly computer literate. You might still have a computer with a DAC and amp (or both in the same box) but I suppose more people will put more money in the downstream equipment for this source unit, and the computer makes ripping and transfers easier. I mean, for one thing, Wadia brought us the digital iPod dock.
