First of all, I must say
tirod3 has a point. He has some very good points from an objective and pragmatic point of view. He also seems to have first-hand experience as he claims to have been a soldier. Thus, I think those are some good arguments and I don't see why you should reply with such childish posts indirectly attacking the man and mentioning mortars and napalm. :thumbdn:
YES, the man asked for a FOLDING KNIFE and I myself carry a knife for SD. BUT, tirod has simply offered some more adequate solutions better suited for the specified task. The facts ARE on his side. It is absolutely true that advancement in weapons has manifested itself primarily in increasing the reach of a certain weapon (and also it's firepower later on). The spear is the perfect example. Initially, it was basically a knife strapped to a relatively long stick. And it was used solely as a weapon with it's main purpose being separation of the wielder and the threat (animals, other humans etc.).
As far as I'm concerned, I'll be carrying a knife in my pocket for a long time nearly everywhere I go. I find it impractical to carry anything else and I have never carried a gun in urban areas. It seems totally useless, at least where I live.
Now, concerning your question, I myself would get an Emerson CQC-12. IMHO it is one of the best all-around folders considering the price. It's a bit bulky but I don't mind that. You should be quick though, as they have recently been discontinued.
Anyway, you should get something with a strong and reliable lock (this is a no brainer) so I wouldn't recommend any liner locks or smth like that. Get a nice framelock or a lockback (best spyderco's have already been mentioned) that is waved or has assisted opening. I myself dislike spydeco's. There are some benchmade models that have potential too. As much as I like Emerson knives I just can't justify a liner lock for anything but light to medium cutting. So, just the 12' or possibly a 7'.
However, as someone has already mentioned, a well built bali can hardly be beat (it can't

).