Did you know that you can automatically set Alarms for certain Activity Types (i.e. Calls, Appointments, Next Actions, etc)? Actually, this has been possible for a long time via an INI file hack, but the newer versions actually have this in User Preferences.
To enable Automatic Alarms;
1. Select Tools | Options from the top level menu
2. Go to the Alarms tab
3. Click "More Options"
4. Check the box next to which Activity Types you wish to automatically alarm
5. If desired, check the box labeled "Show a single alarm for activities linked to multiple contacts", which behaves as expected
6. Ok your way out
You'll notice that now when you go to Schedule one of those Activity Types, the Alarm Date is automatically populated with the same date as the activity. You'll also notice the Alarm Time is omitted. This means that the alarm will happen at any time on the day in question. Try it!