I try and make filters work for me with things like this. I have a folder called "Tomorrow" and set up filters to move mail there from the following categories:
- Departmental/HR/Corporate email (i.e. not my boss or colleagues)
- Mail from particularly spammy friends
None of this stuff is urgent and most of it could be ignored without consequences but some of it is interesting enough to be worth a quick scan. I process it once a day. If I'm particularly busy I glance at the subjects in case there is anything critical and delete the rest. If I'm less busy, I let myself read more of the interesting ones.
The specific part you are asking about is the "Mail from particularly spammy friends". It depends on a lot of things for me. If they sent it to me and only me then it's probably something that made them think of me. I think that's worth a reply. Friends and family are what makes the rest of life worth it anyway. If it's just a chain letter sent to the entire address book then you won't be the only one not replying.