The first rule of knife fighting - is have a gun...
But yes - get some hand to hand training of some sort. Fighting hand to hand is much more effective when you have a knife. I always endorse training in every field possible - then repeated training! You cant learn an art in a 3 day class - or a week at a special camp like place. You have got to keep doing it.
And from the 3 points mentioned - the knife you want - well, most any good modern folder will serve you well. the question is how much you want to spend. And what do you think you will be doing with it other than gutting your enemies.
REKAT knives are great... but are more than twice as much as you need to spend just for a good knife. SPYDERCO makes the best knives out there... Other companies such as Cold Steel or Benchmade make great knives too - Spyderco is just my first choice.
The NATIVES that I just got - wonderful knives. And while effective - dont cause panic in my bleeting coworkers. If you dont like the style - then check out the Endura. Heck if you want to get really nasty - think what you can do with the Spyderco Catcherman in a fight! (a folding filet knife)
"There is no limit to stupidity. Space itself is said to be bounded by its own curvature, but stupidity continues beyond infinity."
RAGE AGAINST THE MACHINE
The Critic formerly known as Kodiac