Actually 1, 2, 3 is good enough. I add in the "and ready" because everybody's enduring for the count of 3 and by then most would have blinked either due to preflash or prediction of when the shot fired.
But given most situations, I just count and fire, because no matter how perfect you count, sure got some buggers who's eyes cannot open one. So even taking 10 shots might not insure all eyes are open.
For group shots I'll give the usual "1, 2, 3-*click*" sequence...and I usually take 2 shots. For the most important I'll spare an extra shot. For those who has the luxury of using DIGITAL this shouldn't be a problem.
What's most important is to prepare your subject--I'll usually ask them to prepare themselves and smile before I do the countdown sequence. Prep-talk does help...