If people ask for advice for a system that will be their primary computer, I have a few pieces of advice I give (which includes SSD and some networking stuff, but question here is CPU).
If a laptop, get an Intel i5 CPU or better. The only reason is that i5 has turbo, i3 and below does not. Look at the first number in the model (i5-5200), make sure to get the newest (highest number), or previous generation if it's more affordable.
If a desktop, same as above, but i3 is OK. Desktop i3 has turbo.
Yes, I am well aware that these will be overkill systems for Facebook and online banking. Keep in mind that this is for someones primary computer - if they're going to do something that requires a computer, this will be the one they use. They're probably not going to replace it before it dies. I don't care if it's overkill for their current use case, the moment they try something out that pushes the limits of the system, they will come to me to complain about my poor recommendation. I can't be bothered. A computer according to the above can deal with most stuff the average person can think of. I do have the luxury that every employed person in this country can afford a i7-6700K every month if they want to, if their spending habits are only somewhat sane.
For specific purpose-systems, e.g. HTPC, professional video editing, gaming, school work, I do research (if I care about helping them).
I'm not an Intel fanboy, I'd recommend AMD as well if their model numbers made sense. With Intel, it's fairly easy to determine basic CPU features (core count, turbo, hyperthreading) without memorizing the entire lineup. I have yet to find any pattern to AMDs current model numbers, and it's easier for both parties if I can give general advice they can apply on their own.