I use TripCase, and manually add meetings etc to the app. For complex itineraries, booking through a travel agent having everything put on the one PNR makes life a little easier also. Interestingly if you have a Qantas booking and add a hire car from your 'Manage Booking' page it automatically adds it to your PNR, also I often find the Qantas hire car rates incredibly competitive.
Beyond that, I also use a spreadsheet with with the columns 'Date, Day, City, Country, Details' and it is about 99.8% accurate back to 1999 with flights, hotels and countries visited. I use it for an overview on forward planning also. This has helped when applying for visas and I'm asked for travel history.