The most popular backcountry shelter is a tent. They are relatively light, weatherproof (or supposed to be), fairly warm, and easily packed. They come in various types and materials and have many uses. Some tents have specific uses, while others are intended to be used for a variety of purposes. Tents can be very cheap or very expensive depending on the quality, durability, etc. The general rule of tent buying is to purchase the best you can afford. A good, high quality tent will last for many, many years, so an initial substantial investment will pay for itself many times over....especially on those stormy alpine days. Tents purchased from a discount store, or that are considered "off-brands," could cause your dream trip to be a disaster.
The best way to choose a tent is to first decide what your use for the tent will be. As said, some tents have multi-uses that will fit the bill for most hikers and climbers. Since this should be one of your major purchases in outdoor gear, getting it right the first time is important. Some questions to ask before deciding on a tent: What season will you be camping? How many people are going to be sleeping in the tent? Do you want your gear to be in the tent too? How long are your trips going to be? Is weight a factor? What shape is important to you? How many entrances to you want to your tent? Do you want the tent to have a floor? Do you want it to be free-standing? How much do you want to spend? So many questions and so many decisions.
Let this solve the problem for you: Most people in the lower-48 states will do fine with a a two-person, three-season, double-wall, free-standing tent. With this type of tent, you can do pretty much anything you want (except for an epic on Mt. Rainier). A good brand of this type is fairly lightweight, is durable and weatherproof, has plenty of room for two people and gear, is easily pitched, and will last for years. However, don't let this sell you. Let's talk about some other types of tents and their uses. Maybe one of them is right for you.
: This tent usually is 1-3 persons, has a double wall, and is designed for spring, summer, and fall use. It is not generally a good choice for heavy winter use because it is not designed to withstand the weight of snow or extreme winds. Double-wall means that the first tent layer is basic nylon (or similar material) and has a mesh ceiling and sometimes mesh side panels. The second layer is the waterproof fly that which is optional depending on conditions. Three-season tents usually have a "bathtub" designed floor which helps prevent floor leakage. Expect to pay from $150 to $300 for a quality three-season tent. Examples of quality manufacturers are: Mountain Hardware, Sierra Designs, REI, Kelty, MSR, Dana Design, and many more.
: 1-3 (or more) persons which is specifically designed for alpine mountaineering or winter camping. They have re-enforced poles and structure designed to withstand heavy snow and wind. They are usually a single-walled tent made of waterproof/breathable material. Four-season tents are generally heavier and more expensive and are also called "mountaineering" tents. These are the ones you see on Everest movies and can withstand extreme conditions. Expect to pay up to $750 for a quality mountaineering tent. Examples of quality manufacturers are: The North Face, Bibler, Mountain Hardware, and Hilleberg.
: Convertible tents can be used for three or four seasons. They have extra poles for four-season use which can be left at home when not needed for milder weather or summer season. These tents are heavier than a three-season tent and are usually double-walled. Although heavier, some find that a convertible tent fits their needs because of the ability to be adapted for in winter use. Expect to pay up to $400 for a quality convertible tent. Examples of quality manufacturers are: Mountain Hardware and Sierra Designs.
: A new generation of three-season, lightweight single-wall tents has recently become popular. These tents are single-wall, extremely light, have minimal poles, and pitch quickly. The tents are made of sili-nylon (or similar material) which is waterproof but not very breathable. The are suprisingly durable yet somewhat expensive. They come in many different shapes including pyramid, hoop, and dome, and are sometimes floorless (to save more weight). Expect to pay upwards of $250-$300 for a quality tent of this type. Examples of quality manufacturers are: Black Diamond, Integral Designs, and TarpTent.
With all the options and choices available, it is beneficial for you to do your research before deciding and purchasing. Many outdoor magazines like Outside, Backpacker, Rock and Ice, and Climbing, have yearly gear guides that can help out with your decision, or you can use the tent reviews on SummitPost. As said before, this should be one of the most important gear purchases. So do your research, save your money, and buy a quality, well-built tent that will stand the test of time and the test of the outdoors. While on your dream trip, the last thing you want to worry about is your shelter.