Warning!
I hope this book contains a warning about the real hazard of building your own computers.
In a few years your house will be filled with bits of obsolescent yet perfectly functional hardware. I recently spent a weekend pulling stuff out of a cupboard and sorrowfully consigning it to the bin. IDE disks, some with capacities up to 500Mb. AGP video cards, and PCI video cards, too. Ethernet cards, some old enough to have coax connectors (when did I last use a motherboard without its own network interface?). CD-ROM drives, usually boasting speeds of 8x and 16x. Fans that fit no known processor. Power supplies that would barely light the LEDs on a modern motherboard. And drifts of motherboards, each with its little tin thing to fit round the ports.
I must resolve not to hoard.
It's not that I'm a bleeding-edge enthusiast. If you build PCs for kids, then sooner or later you succumb to the complaints that the current one won't run any decent games. And now and again I find that I just can't do serious development on a Pentium 4 with 256Mb, so I have to upgrade my own.
Cue replies saying things like "you could install Microbe Linux on that and run your own nuclear power station", or "I develop software using edlin on an IBM PC-XT, and it's never done me any harm".