In reply to ma-ding:
I think the anti-blister socks cause more problems than they solve and as you mention make your feet hot, which is a problem for blisters - I run 1500 miles a year including up to 100 miles ultras and rarely get blisters - if I do it's down to feet getting drenched, or getting grit/dirt in the shoe and not sorting it out in time which shouldn't really be a problem in a road marathon.
The few times I've run a marathon I've just used the thin, cheap pair of Puma socks I always buy online. If you're getting blisters I'd worry more that your shoes aren't fitting properly and fix that, rather than trying fancy socks which are only addressing the symptom and not the cause.
There's probably an element of your feet hardening up/getting used to it over time as well. Also as with any running advice, what works for you might be irrelevant for everyone else.