Most shelters need something to keep them from blowing away. Most people carry metal or plastic stakes, though it is often possible to improvise using local material. A decent video of the big/little rock anchor is what I often do above treeline. Ultralight backpackers often use titanium stakes because they are strong and reasonably light.

There is no one best stake.  There are a number of environmental issues which will suggest what might be the most effective stakes. Things I typical consider is the “holding power” of the stake, how easy the stakes will go into the ground, the weight of the stake, and what sort of environmental impact the stake holes might make.

Holding Power: The looser the ground, the more surface area you need for an equiv hold. If you use two stakes of identical design, the larger on (more surface area) will hold better if you can get it into the ground.  Wide diameter round stakes can work in many conditions, but if you need a lot of holding power, especially in soft ground (sandy, waterlogged, etc), use Y stakes like MSR groundhogs. Some people use V stakes, but I have found that they have a tendency to bent more than most stakes I have tried. In extremely lose soil some people will double stake. At the extreme (sand / snow) you want to use anchors rather than stakes. 

Easy to Drive: The harder the ground the more you want a strong, thin stake. Many people use titanium sheppard hooks stakes. The one down side of these stakes is that if the ground is very hard, you can’t pound these stakes in, you can only push with your hands. Some people carry one “nail stake” which can be used to get a hole started for a hook stake. Note: Pushing V and Y stakes in can be hard on the hands, so I carry a small plastic PVC tee joint which weights less than .5oz.and saves my palms.

Durability: The thinner the stake, the more likely it is to bend. Some stakes have been known to break when put under stress, such as the MSR Needle Stakes. The tops of the Easton stakes sometimes comes off. You can epoxy them back on when you get home.

Weight: If you are shooting for the absolute lightest, titanium stakes might be right for you, but it really depends on the other factors listed above.

These days I mostly use 6″ easton stakes on 3 season trip because they have pretty good holding power in soft ground because they are wider than my titanium Sheppard’s hooks, and the have a flat head so I can pound them into harder ground with a rock, and they are reasonably light. The only down side is that the epoxy that glues to top to be body can come undone and in extreme cases, they can be broken.  If I am really concerned about holding power (expecting lose soil) I will switch to 9″ easton stakes, or switch to a Y stake.

Jerry Goller wrote up a more analytical comparision of stakes which I have stashed on my web page and there is a nice article at BPL about tent stake holding power.

Snow anchors are a good alternative to stakes in the winter or in deep sand.