If you don't mind a lockback,and aren't extremely tough on your knife - I nominate the Spyderco Stretch 2. The black FRN handle version with VG-10 steel. If you look around it can be had for around 70. Very light, and slim in the pocket. Has a thinner blade than many of it's Spyderco siblings so it slices like crazy.
I would have to say the Spyderco Resilience/Tenacious/Persistance/Ambitious line is probably the best for the money that I'm aware of. Usually they can all be had around $40 or less. Great G10 scales, decent steel, and a very good layout.
I'm not going to use it for anything unusual, nothing too rough, just cutting or opening things here and there. But I want it to be sturdy.
I thought about Spyderco Endura, anyone using it?
The Endura is in my rotation also. I think you'd be pleased with it. The variant with the flat ground blade is especially a nice performer, though there's nothing wrong with the original saber grind blade either.
Spyderco knives are great all of mine have been a pleasure to use and carry.
I would seriously look into the SOG line of knives though, I have the Flash II and it is incredible. I now leave the spiderco's on my dresser or stashed in my climbing rucksack.
SOG Twitch II it's around $50 at any local Lowes, perfect size and it is tough as nails! I've carried the one I have everyday for the last 5 years with no complaint other than I need more stuff to cut with it...lol. Had to edit to mention that it's assisted opening as well....
I've carried a Spyderco Endura 4 for a couple years in thEquine Transport business. It's held up well. Light, thin, retains the edge better than most I've used.
Lovely EDC for my purpose. YMMV
My vote goes to Kershaw,the reason is that they have great customer service and offer free repairs. I have a couple knives that needed repair and they took care of them with no problems. They even sharpen the blade for free when you send it in and they put a excellent edge on. If you look around you will see they offer several different models ,I like the assisted openers.