I've done both - Den Meeting at the church (the chartering organization) and Den Meeting in my home. Both settings have their advantages. When I'm meeting at the church, I have an incredible amount of space, unlimited seating, adequate classroom-style lighting, and contact with the other den leaders. When meeting at home, I have a comfortable setting, I'm always on time, and I have ALL OF MY STUFF!
I bounce between the two settings as needed by my program for the night. Making placemats for Blue-and-Gold? Church setting - they have lots of long tables that are built to handle glue spills. Teaching Webelos campfire safety *before* the campout? Home setting - build the fire ring in my backyard. You get the idea. As long as you are good with communication and maps, this works very well.
I've seen the light and dark side of having parents in place (fortunately, more light than dark). Parents are an asset, and I'll use and abuse anyone who is generous enough to lend their time and talent to my den. This approach has enabled me to lead for four years without an official assistant den leader, but at least five "unofficial" assistants!
However, I've had some boys who were absolute angels of behavior due to the unfamiliarity with the Den Leader - in short, they don't know how far they can push me, so they don't push too hard. Bring Mom or Dad into the mix, and they are suddenly more comfortable, knowing just how far they can push, and so they do - to the breaking point! To such parents I try to give jobs that don't require their presence, like bringing cookies to the pack meetings or campsite preparation on outings.
One question for Acco40 - you mentioned that a husband/wife doesn't constitute two-deep leadership. I'll agree that a husband/wife team isn't an ideal example of two-deep leadership, but I've never heard this was specifically disallowed. Not trying to start an argument or anything - the reason I ask is because I am a district trainer, and I'm constantly asked about the permutations of two-deep leadership. When asked about husband/wife teams, I refer to the BSA policy that there must be two adults present - two registered leaders, or a registered leader and the parent/guardian of one of the participants who is at least 21. However, I usually add that the youth-protection guideline is for *adult* as well as youth protection, so a non-related adult is better to provide more accountability, but that it isn't *required*.