My husband and I generally agree about discipline, but there have been a few situations where we didn't. Mostly when that has happened we have agreed to let the punisher (whoever witnesses what happened - usually a fight between the kids) have the say on what the punishment should be. We learned early on to back each other up, because the kids will play the parents to get what they want. I may not agree about a time-out or a toy taken away, but I think it's important to show the kids that I stand by their father, or that he stands by me.
Granted my kids are only 3 right now, so the punishments are pretty basic. I hope that when they are teenagers and we're talking about grounding or taking phones or video games away, that we still sit this equally on punishments.

I agree, backing each other up is important and showing a united front. For our older kids, 10 and 8, we often discuss the punishment and incident with them. The ground rules are set as a family early on, so they know the deal before heading down that path. We talk openly with them before, during and after to make sure they learn from their experiences, see how adults handle things and as a family how we work together. Really, what we have found, is that raising them through these experiences is the part where they learn and the results in adulthood are what they become vs. just a punishment.

Thank goodness we're on the same page when it comes to disciplining the kids. When we have disagreed about consequences for various actions, we discuss it privately so the kids don't try to play us against each other. They know if one of us says no, we both say no.

I will say, having my husband home for spring break has been great so far. I'm not the only one in charge all day - so it's actually a break for me as well!

If one of us disagrees, we never say so in front of our teens. We always take it behind closed doors. We will listen to each other's opinions and usually come up with a compromise.

If we still have conflicting ideas in the end, the one who is bothered most by the behavior, doles out the punishment. We really try to ensure that they never know there was controversy surrounding an incident. We will just agree to disagree and try to move on as quickly as possible.

It's been a very rare instant that my husband and I have disagreed on discipline issues. We also, like many of those commenting above, never disagree about the 'consequence' one of us has chosen, in front of the children. That being said, the 'disagreement' is usually not a disagreement per se, but rather we're just talking through our choices later on and realize there was probably a better approach to the situation. Fortunately, have always agreed upon a solution for future issues.