@OP: You can also consider other prebuilt solutions like the Zotac Pico or Minix (several models - both ARM based and x86 based - and both Android based and Windows based).
ZBOX pico: ZOTAC - It's time to play!
MiniX Products
They are in the $150-$200 price range and so not that far off from the Chinese options. And these are fully built up with RAM and storage and OS preinstalled. Barebones small form factor PCs are quite finicky and hard to build up and often the cost exceeds the cost of fully built up options.
@Venkatcr - Good to know some insights about Intel's NUC strategy (or lack of it), especially from someone close to the action.
As a long time watcher of this space, and investor and being fairly close to it, I would still say that the final word has not been said. Intel is still testing the waters. NUC was an experiment and perhaps it will get rid of it. However, it will still listen to its ecosystem carefully. Gone are the days when Intel was the only game in town and could push around its ecosystem partners.
So if a big vendor or partner for example insists in Intel continuing to support very small form factors (not just NUC - but there are a bunch of others), Intel will indeed accommodate. Just as it bends over backwards for Apple, one of the few partners which buys Intel's flagship (expensive) products.
The problem with Intel is really not dwindling market share. It is dwindling profit margins. Intel has long enjoyed extremely good profit margins because everyone was used to paying $1000+ for PCs and laptops, even back in the day. With ARM came not just power efficiency but throwaway prices. And now everyone expects to get desktops and laptops at rock bottom commodity prices. In the $200-$500 range.
I would be a rich person if I could predict the future. But we are living in interesting times. While Intel's products (CPUs) were not competitive in terms of performance and power consumption, the current gen coming out (Cherry Trail and the tock generation products of the tick-tock cadence) are really strong options to the best of breed ARM. Core M is already starting to appear in fully fanless designs.
I recently purchased the Asus Zenbook UX305 which is fully fanless, has Core M, runs Windows 10, has 8GB RAM and 256GB SSD, has 10+ hours battery life, has decent integrated graphics, is made with machined aluminum, and is one of the lightest and thinnest laptops around. At about $600, to me, it represents phenomenal value for money, and what laptops should always have been. Dell XPS 13 is another phenomenally well built laptop, although a bit pricier.
I am digressing a bit, but I wanted to add that there is more to it than meets the eye. For example, if Steam Machines (gaming box design similar to XBox One and PS4, but PC based, not based on custom design - and based on the Windows/Linux cross platform Steam software), it will be a more compelling reason for more people to go for a living room PC (but in various form factors and sizes) that can perform various functions - HTPC, quality audio player, gaming box (lightweight or heavyweight), streaming audio/video player, storage solution (lightweight NAS), etc.
A variety of devices have tried to address this in a multitude of ways. Many, half hearted though. AVRs pretend to be streaming audio/video devices. Streaming players like Roku pretend to be audio players with USB and network support. Fanless small form factor cheap devices like Minix pretend to be HTPCs at a fraction of the cost.
The main problem with desktop class solutions is space, noise, and price. Especially for a product class that is so rapidly evolving - it might even make sense to go for extreme low budget solutions like what OP is suggesting. Worst case, Intel pulls the plug on NUC a year down the line - it will still take several years for parts to finally disappear from the market. And enough quality products like Squeezebox have bitten the dust.
