Sleeping pads are not just a comfortable luxury on the trail. They can be an important barrier between you and the ground. This is useful for a few reasons. On multi-day trips, it can spare the body some unnecessary soreness. Sleeping pads also help prevent the cold ground from leeching warmth from a tired hiker's body. In the event of dampness coming through the tent floor, a pad will also help keep the bulk of a sleeping bag dry. There are a few points to take into consideration when investing in a sleeping pad below are two different routes to take.
The Therm-a-Rest Z Lite Sol is a simple accordion-style design. The pad folds down to 20" x 5.5" x 4" if you get the 51" option (the 72" is an extra inch of thickness when folded). Therm-a-Rest claims "a new, aluminized surface reflects heat, increasing overall warmth by nearly 20%" which is difficult to substantiate on the trail, but is a nice feature if it's true.
The Z Lite Sol is lightweight, as the name implies. The shorter option is .6 pounds and the longer is .9 pounds. The concern when packing is not the weight. Because of the material and design, it can be difficult to get the pad into the a pack along with other gear. Strapping the pad to the top or bottom of a pack is not a major drawback, but it can be less than ideal because of the possibility of snagging on branches or getting wet in the rain.
As for comfort, the egg crate design gives more padding than one might think at first glance. The foam is sturdy without being overly rigid. The Z Lite Sol is a solid sleeping pad at $35 for the short option and $45 for the long. Even a taller hiker can get by with the more affordable, smaller, and lighter short pad if he or she is willing to let the lower legs go unpadded.
Another option is the inflatable mattress. Therm-a-Rest first patented the self-inflating mattress in 1972 and they are commemorating the original with a 40th Anniversary Edition. Deflated, the mattress packs down to 11" wide with a 4.8" diameter. Unlike the folding foam mattress, the inflatable pad has some flexibility when packing it tightly into a backpack.
The 40th Anniversary Edition inflates to a tapered semi-rectangle. The "women's version" -- by which Therm-a-Rest really just means "shorter version" -- is 66" x 20" x 2" when fully inflated. Weighing about 1.5 pounds, the pad is not a significant weight burden.
At $130, the women's version 40th Anniversary Edition is a bigger expense than any foam pad but offers more comfort and packing options. Take these two options into consideration when outfitting for camp. Be sure to compare prices and shop around for other brands.