The perfect Eggs Benedict requires a perfectly poached egg. To poach a medium-sized egg, bring one gallon of water plus one cup vinegar to a slow boil or simmer. Put eggs in individual cups or ramekins and slide carefully in the water. Do not salt the water when poaching eggs (they'll come apart in the water if you do), and look for the freshest possible eggs. Let cook for 3 minutes and 10 seconds. When making the hollandaise sauce, be sure to use separated butter, and don't overcook the sauce.
Also, only make as much Hollandaise sauce as you'll use, since it generally does not reheat or store properly. (One trick is to use a thermos to keep it warm.)