Keeping all of your trip details is a PAIN. Making sure you got the Flight, Hotel, Rental Car, Restaurant Reservations, Address, Phone Numbers, Contacts, etc. But last year i found out a great solution that keeps track of all of that for me and I want to share it. The website is called TripIT! It builds you an interactive itinerary based on your confirmation emails. Basically, when you get the email that confirms your booking at your favorite Marriott or SPG hotel, you simply forward it to email@example.com . Then do this with the other things like Rental Car, Flights, OpenTable, etc as well. Once you have everything sent over, simply login to TripIT.com on your Computer, or using the Tablet / SmartPhone app and you have instant access to all of your travel plans.
And no, I do not make any money or work for TripIt. I just really enjoy the product and it works really well.