Software is all about default behavior. From pure infrastructure plays (e.g. Gnip) to general population consumer facing applications (e.g. Apple products).
Whether you want to call your software's configuration, "preferences," "settings," "configuration," or "config," they're all the same, and the choices you make about their default values define your product, and how your product will be used by the vast majority of your users.
If you screw up a "default" setting, from whether or not a calendar entry should "remind" the user that it's there, to how XML is generated, you will find that out when your users engage with your product; or not, as the case may be.
Coming from Netscape/Mozilla, one of the most configurable products known to man (just type "about:config" into your URL bar to see what I'm talking about), and now being a heavy Apple product user (where giving the user options is considered a design flaw), I'm trying to strike the right balance between default behavior decisions and giving end users control of Gnip.
By default, do the right thing.