Don't be too hasty to pre-empt us non-mod users: as this site grows, you'll need us to do more and more of the janitorial work. Generally, we've been pretty good at closing bad questions, and deleting bad answers. Moderators are there to handle the exceptional circumstances.
As others have said, suspension is a last resort. Give a friendly specific warning when you see undesirable behaviour: but do not threaten. Do not say "if you do X again, I'll suspend you". Instead, try something like "behaviour X is not welcome here. We're just here for the questions and the answers - please do continue to contribute those". Shog is an expert at handling misbehaviour and in communicating the rules deftly - watch how he does it on the mother meta, in the Teachers' Lounge, and elsewhere.