I know this is less programming related and more time management related, but I value the feedback of the users on this site. I\'m finding myself particularly busy this semester
I like Google Calendar - you can put in all your deadlines, meetings, appointments etc. Its web based and free. You can have multiple accounts on the same calendar like work and home and it will even send reminders with sms.
There is a Remember the Milk plugin of course for your todo list.