Part of packing light means that your phone truly becomes multi-functional. Not only does it continue to be your lifeline to friends and family, but it's also your boarding pass, in-flight entertainment, camera, map, translator and guide to the best restaurants in town. Since your phone is an extension of you, it's important to carry a portable charger in the likely event that the battery dies in the middle of the day when you are nowhere near an electrical outlet.
Tripomatic I just discovered Tripomatic last week, but I know that it's going to be crucial for creating itineraries for European vacations. Not only does it have city maps (unfortunately, to gain offline access, you have to pay), but it also contains a list of all of the most popular attractions that you can add to your itinerary and then switch around based on proximity to each other. They also have a whole slew of guided tours and activities that you can add to your trip if you would like a little bit more context and explanation about what you are looking at. After taking two coach day tours in Scotland and Ireland, I highly recommend them as a way to see and learn a lot without having to do a lot of planning.
TripIt TripIt is a must have for all vacations, whether domestic or abroad. As you receive confirmation emails for flights, hotels, attractions, rental cars, etc. forward them to TripIt to keep them all in one place. Although I'm still one of those people who will keep a paper copy of reservations in a folder, it's nice to know that I'll only have to dig through a mountain of paperwork as a last resort.
Rick Steves Audio Europe Too cheap to pay for a city walking or bus tour? Say what you will about Rick Steves, but he has provided free offline walking tours of all of Europe's major cities that last between 1-2 hours. I haven't listened through any yet, but I can't imagine that it could be any worse than aimlessly wandering around admiring the architecture or people watching and that's it.
Google Flights Although not a downloadable app, I'm such a fan of searching flights on Google rather than Kayak. The interface is much more clean and uncluttered. The fastest and cheapest flights are grouped at the top of the list depending on what matters most to you. It is also easy to compare prices month to month if you are extremely about your dates of travel. Plus, once you have selected an itinerary, you can save it to track the price as well as email it to friends and family so you can all rest easy knowing you are all booking the same flight.
CityMaps2Go Paper maps are a thing of the past. Download the maps you will need before you depart and have offline access. It's a game changer.
Duolingo I like the repetitive nature of Duolingo and how it turns language learning into a game and combines writing, listening and speaking the language to get a better feel for it. Don't expect to become fluent through this system, but you will be able to navigate the street, and most importantly a menu, by the time you are halfway through.