Travel planning has been gradually shifting from the domain of experts to the domain of an ever-growing amount of travelers' experiences, and it will continue to grow in that respect in the years to come.
With the advent of the Internet, most travel bookings and travel research have moved into the online space. Guidebooks are excellent resources on the road, but they quickly become outdated when the Internet is constantly updated with newer and more accurate information. User-generated sites such as wikitravel.org are updated by locals and travelers as soon as new restaurants, hotels, and bars open, and these people also are able to "vote" with the information they put online. Other booking sites now rely on the reviews of other travelers, and services like Twitter allow instant broadcasts of what travelers' are experiencing. With all of these resources available, online travel planning is the best method. Here are some of the best sites to use:
o Wikitravel.org is one of the best travel sites on the web. Modeled after Wikipedia.org and easily searchable by location, and offers the most up to date information available.
o The Thorn Tree travel forums moderated by Lonely Planet are legendary. Tens of thousands of travelers that have almost certainly seen and done whatever trip you are planning are more than happy to lend a helping hand.
o Kayak.com is an airfare search aggregator, covering most of the world's major airlines. It will find the best prices based on your travel preferences, then take you to the site of the carrier to easily book your flight.
o Hostelworld.com is the king of cheap accommodations. With over 10,000 network hostels, the website has budget locations all over the planet, all searchable and ready to book online.
o Couchsurfing.org is a fantastic website both for connecting with locals while traveling and securing free accommodation. The website allows people to host travelers all over the world for free, and they often serve as tour guides and the perfect local guidebook for a place.
A lot of the above websites have the common factor of user-generated content. This is increasingly becoming the determining factor for travelers. The reasoning is that most magazine and guidebook reviews are paid, so reviews posted by other travelers are inherently more trustworthy. Taking a look at a guidebook published 6 months ago on a city like Buenos Aires and comparing it to the Wikitravel.org page is like night and day. The old methods of travel planning have been replaced by the immediacy of the Internet and the amassed knowledge of other travelers. As more and more people gain Internet access, even remote places will have locals that can dispel myths and misconceptions about travel in their hometowns and areas.
This spread of information will make travel planning easier and easier, and also more accurate. I have planned all of my trips abroad using solely the Internet, and it is by far the most efficient method.