I just got a msd coil and think its to powerful because my spark plug wires are flashing by the plugs when you look at them at night. My msd wires are brand new and so are my ac delco platinum plugs.
+1 with leadfoot, I doubt the coil is the culprit behind the flashing but if you have another one handy, you can give it a shot.
FWIW i had the same problem you are experiencing last year post GDL'09, while running an OE coil.
I had plugs flashing, mine were inconsistent and random, like every 4 seconds or so #1, #3, #4 and #5 would put off a blue, mini strobe-like flash.
It was bright like an arc, but if you watched those plugs intently, you could see it was the porcelain of the plug lighting up bright blue for a split second.
They were AC Delco Double Platnum with around 30k on them.
Long story short, I had bad plugs, either outta the box, or I hair-line cracked them during installation.
I went back with a set of standard NGK TR55's, seeing as all the platinum pucks were already gone off the AC's after 30k (also causing my plug gap to open up massively), and I haven't saw the plugs flashing as I described since.
Take note that if in pitch black darkness (no hood light), I can still see all my plugs barely,
barely "blinking" as the motor runs, but its not random, and not bright at all. (I always saw this, but it's nothing like the bright flashing I had). I believe this light "blinking" is normal, as I can see this particular "blinking" on my 95 Yukon as well.