I agree most with the recommendation for the Lahar. It provides the most bang for your buck. An excellent knife, respectable steel, discontinued, and relatively uncommon. And can, surprisingly, still be found for a reasonable price (under $100). One of the few non-pm steel knives that I actually own... In fact, I had to pull mine out for awhile just to fondle. ...my knife, you dork...
You would definitely be doing right by your father with a Lahar.
An s30v Blur would also be pretty darn cool. And you wouldn't be skimping on the steel.
Good for you. You have a fortunate father.