With all the tools available to use to organize trips, Travefy is by far my favorite. It has almost everything I need all in one place.
I have used it plan 16 trips so far which range from solo, to with my husband, to girls trips.
It is first and foremost an itinerary builder that allows the organizer to invite people to the trip. From there the members of the trip can suggest ideas and chat on a discussion wall. You can then decide how many emails you would like Travefy to send you with activity updates so you no longer need to be drowning in endless email chains.
It has places to add flight information, restaurant reservations, and costs for items like museum tickets or other attractions.
Once you are done building your itinerary they also have a handy mobile app that has everything you need while you are on the go.
Best of all, it is totally free.
And yes, my avatar is Grumpy Cat.