I was just about completely convinced that it'd be silly to do so nowadays with the low price of consumer-ready systems. Even the whole idea of a 'PC' is nearly history. Let me explain my problem though.
For everyday use, we use a notebook computer on the table. When I got rid of the old tower case, I really didn't. I hid it behind the wide-screen TV and it became the media server. Over the course of the past couple of years its role has actually increased. It now serves Netflix, Hulu Plus, YouTube, Network TV, and other assorted video directly to the television. Being connected to the home theatre system, it also plays radio through TuneIn and Pandora as well as my own music collection via Google Music. So, although the old tower hasn't helped with a Word document or Excel spreadsheet in years, it has actually worked harder in its newer, default role.
At around six years old, I think it's time to replace the old tower with something a little more efficient in both space used and power consumed. I put on an evaluation copy of Windows 8 about a year ago. Now it insists on reminding me to upgrade to the full retail version every time I switch it on! Either the motherboard or a RAM (DDDR2 only) chip must be getting on its last legs. I get occasional system crashes at absolutely random intervals.I was very seriously considering looking for an Asus EEEBox or a newer model running Windows 8. There really is no financial imperative to buy anything other than a box which is ready to plug in. Yet, when I was looking at my favourite computer shop's website, I found new and exciting things. Ooooh! What are these MniITX cases and motherboards? I have been away from PC-building so long, I didn't even know that such cute little things existed.
I fear I may end up building my own mini-PC media server simply for the pure geeky fun of doing it!