I am going to say the kind of dickish thing, but only because you said the following:

My fiance & I are on the fence about whether to include children or not at our wedding.

Here's my pitch: allow kids.

Empower parents to make their own decisions. There are people out there who are going to, on their own steam, get a sitter and have a grown up evening. There are people, for a whole host of reasons, want to bring their kids because that's what makes their lives easier. And I've been to a lot of weddings with kids and it usually handles itself. Young kids need to go to bed and no parent worth their salt is going to keep a four year old up past nine. Grade school age kids just want to dance, and still need to go to bed at a reasonable time. Middle school/high school either doesn't want to be there and wants to go back to their hotel room asap to get online, or they can legitimately have a good time dancing and talking with family.

Moral of the story: parents, least of all, want their kids to be an issue. They want their kids to sleep at a regular time, not throw tantrums over food or exhaustion, to be pleasant and polite...most parents want this. And if they know or fear they can't have it, they either politely decline or they get a sitter.

I know what you hope for, but that's really limiting for all parents. Giving them the power to make that choice for themselves might mean the difference between them being able to come or not. And unless you very specifically want an adults-only event for your OWN reasons (not the comfort of the parents) then you should really rethink it and restate your intentions.

I am playing Devil's Advocate. I totally appreciate and respect an adults-only event. It's about a mood, a tone, and what you want the thing to be. There are events appropriate for families and event appropriate for adults, and both of those are viable situations for a reception. But if you're going to do it like that, make it about that. Don't tell parents that you're doing this for them, because removing the choice isn't a gold star, it is a way of limiting options.