Ask HN: Spectre/Meltdown and New Desktop Purchase?

The Windows PCs my friends' own are dated, due for replacement and they are asking for recommendations. They're all small-business + web surfing users (no developers, no gamers).

Is there a preferred architecture given the Spectre/Meltdown situation?

And what _is_ the "Spectre/Meltdown situation"? Is there a trustworthy clearinghouse of information about this problem?

For myself, I run Linux and do my best to keep the system updated - but is that enough? Do I need a newer, safer CPU (and consequently PC)?