What Hlee said is right on. It's just like someone saying, "I need a gun. What should I get?" There are many different considerations. I have two Ka-Bars that my dad took through the second world war. They're sharp and tough as nails, and my dad scratched the names of all the places he visited during the war years in the Pacific. Both knives could still pull full duty for the rest of my life. I have a number of fixed knives and folding knives and they have many different uses. Are you looking for a tough, outdoor knife for camping? As strange as it sounds, I just got a Smith & Wesson Homeland Security Tanto that I've fallen in love with. Yep, that's right. Smith & Wesson. I NEVER thought I'd recommend a S&W knife to any one for any reason, but there it is. And the blade is stainless, too, which is something else I don't usually recommend. But I found a good price on the S&W and I liked it so much that I turned around and ordered four more of them!
But it's a matter of what you want out of a knife, how it feels, performs, and how much it costs. Some folks don't like tantos and a whole bunch of people don't like S&W knives, me too, most of the time. Some want a double-edged knife, or a Bowie of some kind. Others want carbon steel and some prefer stainless. Some want the blade coated black or camo, and some like a flat, brushed steel color; and then there's wood handles or G10 or some kind of rubber. And we haven't begun to talk about sheaths!
So perhaps you can tell us more....