For blade steels, I would get something that is very tough so as to resist damage large and small, this is for a large chopping class knife of course, for a small utility blade you would go with other steels. So in general you are looking at steels like L6, 5160 and the plain carbon steels like 1084 (lots of others of course, these are just some common ones). Some of these steels can easily get very hard, but you want durability so the HRC should be ~58 to maintain flexibility.
Steels like ATS-34 are very strong, but will crack with almost no give when overstressed. Strider makes very thick blades so this is not easy to do, but still, for that kind of knife I would want it to give before it breaks for many reasons. This is not only relevant to the main body of the blade but just the edge. Consider whacking it into a hard object, the edge will deform, and you don't want it to fracture readily, but instead bend and impact.
For a blade design, I would keep it simple. For this you really need to know what you are doing and what else you have. With only one knife then you want to keep the design even more general. A very thin point for example makes a lot of precision work much easier but limits scope of work. I would personally use a drop point or even the traditional tanto (not the cold steel version) to keep the tip strong, with the Swamp Rat military or penetrator tip to enhance penetration.
The blade profile should be wide enough to give good cutting ability, which is about two inches on 1/4" stock. You want the edge ground nice and thin, about 0.035" after sharpening (15 degrees per side, 22 degree micro bevel for durability in extremes). This leaves it thick enough for even the hardest of impacts without danger of rippling. That edge thickness is based on my use (I would go with a 10/15 degree split on the edge personally), if you are a real brute you might need to go thicker, but even 0.035" has a decent safety margin. Seriously if you have the ability to ripple that edge chopping, you probably don't need a knife and can just haul trees down.
For the blade length, I would not go much under 10" in a one knife senario. It just becomes too awkward for brush work, and this is a large part of gathering materials for shelter construction, fire, bedding, clothes and food. Personally I would go 12"-14" and all these tasks now become much easier. Above 14" and it starts to become awkward for me to do knife like work with the blade. Your own physical abilities play a part here of course. Now the precise cutting chores do start to become awkward here with the longer blade lengths, but in general these are not nearly as physically demanding anyway.
As with most of these factors there isn't a right or wrong. I would choose 1/4" blade stock for example, but this may be too heavy for some and thus inefficient. In that case a 3/16" blade would be much more efficient and more functional. In some cases physical ability would allow even heavier blades like the very large khukuris that are often offered by HI. There are quite a few people happy with these large blade. I am still working on being functional with brush cutting with my 22" Ang Khola.
-Cliff
The accessories tucked into the outer layer of the sheath are a Gerber diamond sharpening rod along the spine of the blade, a Seber-Tech M4 mini-multi-tool, a Swedish military model Firesteel with scraper, and an orange flat whistle.
