What's a good day planner/calendar program to remind you of your day's appointments, etc.

I am looking for a program to launch at start up on a Windows machine that will remind me of the day’s appointments, must do projects, etc. Sort of a great secretary always there when I walk into my home office to get me aimed at what needs doing. Plus points would be flexibility for calendar functions, look ahead reminders, organizer, day planner, exportability of files (CSV?) and reasonable pricing.