Thanks danielagos -- your post woke me up, made me realize I had been asleep at the wheel, assuming I was stuck with the all-day default since there was no "preference" setting available. I myself am opposite from subject of post. I prefer working in monthly view, but rarely have all-day events. I detest the alI-day default for new events. I have been using right-click to create new events, not thinking about behaviors depending on how I create a new event. Now I can kiss all that annoyance goodbye. I played around with the New Event options in monthly view (which I should have done long ago) and found my solution.
Turns out, in Mavericks iCal, all-day is the default in monthly view only IF you do not enter a time in the New Event description window. That first little window we get when creating a new event is not just to name the event -- it's to quickly tell iCal about the event you want created. Thus, changing the "default" event duration is as simple as changing the way we create a new event. That is, feed iCal the desired information in a simple string right in the new event entry window and let iCal populate the new event.
To create a new event, you can use the Menu, enter Cmd-N or right-click and select New Event. (May be other ways but those are all I explored.) If you enter the TIME and/or day in that first small window which opens, iCal knows what to do For example, you could key in "7am Garage Aug 2" or "Garage 7am Aug 2" whatever and iCal will create an event on Aug 2, with start time of 7 am and title of Garage. If you key in a day of the week instead of date (Garage 7am Fri) while usng the menu or Cmd-N function, then iCal defaults to the next occurrence of that day (next Fri, e.g.)
iCal does have slightly different defaults for the event duration depending on whether you are using the menu/Cmd-N functions or the Right-Click function.
With either method, the default is all day if no time is stated in the initial new event window. The Cmd-N method will default to one-hour duration if you give just a start time. If you want more than one hour, you must state the start and end time (e.g., 7am-10am Garage Aug 2), then the new event will show that duration.
With the right-click option to create a new event, stating only a start time will give you an event of one-minute duration. If you want longer, you must state start and end times. Again, default is all day if no time is started.
At least, that's how it has worked for me, so far. :-)
Anothr difference is what happens immediately after the event is created. Cmd-N function automatically opens Info, allowing you to quickly verify accuracy of entry and make edits. By contrast, the right-click option does not open Info; if you want to check for accuracy or make edits, then double-click on event to open Info.
Mavericks 10.9.4