Great idea! Other topics I can think of...
House related (buying a house, or decorating- like others have mentioned)
Finances (if/how to combine them, how to budget, how to invest, etc)
Relationship oriented (ya know, how to keep that newlywed spark alive even when you have to clean pee off the toilet seat?!?!)
definitely an In-laws or family thread and a TTC/Prego thread...
That's all I can really think of for now!