For great knives at a sensible price I would look at some of Spyderco's, Benchmade's and Kershaw's offerings. Assuming you're looking for a folding knife.
$150 is a pretty good budget for a knife, you can get some interesting ones.
The basic Spyderco models, Endura, Delica and Native are quite good. The steel they use is great (VG 10 for the Endura, Delica and Native III, and S30V for the US made Natives). You can get either of them for under $60 from online retailers (I can recommend Shop for case knives, Kershaw and other discount knives at Knifeworks.com
, great service). The US made Natives are even available at some WalMarts for around $40! That's a great deal on an American made knife with great steel. Some of the nicer Spydercos are also well withing your price range, if you want a tough as nails knife, look no further than the Manix. It's built like a tank.
Benchmade's Griptilians are also a great choice, you've got plenty of blade styles to choose from and two sizes (full size and "mini"). My favourite is the original 550 Griptilian, because I prefer the opening hole to thumbstuds (I don't like things protruding from my blade). There are quite a few BMs under $150, I would look for one of their axis lock designs or at the fantastic Dejavoo (one of my favourite Benchmades ever!).
Kershaw has some of the best bang for your buck offerings in the knife world, and they make them in the US! I've sold a few dozen of the basic Kershaws at my store and my customers are thrilled with them (knives like the Storm II or Skyline). For under $100 you can get one of their assisted opening knives with S30V blade (like the Blur or Avalanche).
There are lots of other good brands within your price limit: Emerson, Al Mar (the SERE folder is just a couple of bucks over $150), Lone Wolf, etc.
If you don't already own a quality multitool, I'd split the $150 between a good folder and a good multitool. For instance a Leatherman New Wave ($70) combined with a Spyderco Endura ($60) would be a nice combo for almost any daily task. If you spend a lot of time outdoors you can add a good fixed blade knife later on.