the bushman is decent for most outdoor/camp/bushcraft uses, although a little big. Moras and puukkos are great for survival/firestarting/wood gathering. The one caveat to a smaller knife like a puukko or a mora is that you will not be able to chop effectively with it. The gerber big rock is a decent all around knife as is the KA-BAR.
Also, there is no such thing as "knife combat". This link should be helpful..
http://www.nononsenseselfdefense.com/knifelies.html
If you're looking for defense, carry a gun. There is almost no threat that warrants the use of a knife as a defensive tool. And there ceratinly arent going to be any knife duels in your future. There are much better alternatives, like rifles.
Have fun and be safe.