The only games I earnestly use a strategy guide in are PC Adventure games like Syberia, King's Quest, etc. Then, the only time I actually use a FAQ is when I'm certain I've just missed something because I refuse to pixel-hunt anymore (anyone who's played PC adventure games knows what the pixel-hunt is), so it's more a matter of not finding something that's too damn obtuse and not a brain-power thing.
I did own the strategy guide to FFVI (when it was released as FFIII in the US), but I didn't use it, I just got it for the art.