Nice, I most always have a Kershaw Storm in my pocket. It's no designer knife but very well made for the money.
http://www.amazon.com …e-ComboEdge/dp/B0013CK5GS

Kershaw Scallion.

~$30 - so WHEN (not if) you loose it, you won't cry.
Easy single handed open close.
holds a good edge.
not too big, but big enough - not gonna scare anyone with it.
I recommend removing the safety as it can be sticky at inopportune times. (very easy - just take out a screw). I don't the version with serrations (true of any knife) - can't sharpen.
I have a couple. One is always on me.