My kids are 4 and 6 right now. Yesterday we tired the kids out, and they behaved very well and then passed out early! So basically, exercise did the trick.
Other than that, we still use way too many bribes... but don't really use threats any more. Most of all, we rely on creating and sustaining a bond with the kids - that's the biggest trick for us in getting the kids to listen!
What's been working for you lately?