Andrew Gabriel wrote:
What I have seen several times is damage caused by a surge
induced by lightning on a phone line. Of course, the mains
surge protector will do nothing to protect against that.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Not in my opinion.
If I saw something at less than rip-off prices for protecting
against surge on phone line, I might consider that.

I have a surge protector which includes protection for the phone line,
so that's where the ADSL modem gets plugged. Whether it would actually
work or not is another matter of course. My complacency lies in not
bothering to research the matter thoroughly, on the grounds that if I
was buying snake oil, it was at least *cheap* snake oil...

For the mains, online UPS is the proper solution, but I can't say I'm
unduly concerned about not having one. Power provision in the UK is
fairly reliable at the moment, although political and business
imperatives will probably conspire to make it worse in the future.