I concur with the great place comment, just dropped by and been here a few hours! This is my first post!
I have quite a number of knives, what it comes down to is the intent of use and personal preference. Also, make sure you check your local laws and that carrying a knife does not constitute possesion of an "offensive weapon". If you are in Florida have a look at this
http://www.freedom4bunkley.net/.When you look at folders, you want something with a good lock (there are many to choose from - liner locks, lockbacks, axis locks, framelocks etc.., a good steel (m2/d2 tool steel is sensational but very expensive, stick to something you can maintain a good edge on and sharpen without too much difficulty, something like ATS-55 (used on spyderco's) or a 440 steel), next is blade shape (clip point, tanto, drop point, bowie) which again comes down to use and personal preference, then you have the plain vs. serrated choice.
I would recommend to always get a plain edge. If you want a serrated edge you can always roughly sharpen (using a low grit stone) a portion of the blade to give it a type of serrated edge. Advantages - easy to sharpen, better to control (serrations tend to "bite"), can also rough grind a portion of the blade, if you get good at sharpening you can shave with it! If you want to cut through seatbelts, buy a Benchmade rescue hook - also doubles as a bottle opener and emergency oxygen valve opener.
When it comes down to it, with the manufacturers you are looking at, you will get a quality knife. Maybe have a look at CRKT, Benchmade and Kershaw as well.
I agree with the comments on the Delica - I keep one in the car, it's a great knife and good value for money - easy to open with one hand. That, accompanied with a surefire will keep you in a good position.
But as people have mentioned, go feel some, find out what you like, but you are better saving up and getting something decent that will last and not let you down when you need it, rather than getting a cheap knife that has an average locking mechanism that might let you down when you need it most.
So all that said .. what should you look at?
I would suggest having a look at the following:
Cold Steel Recon - decent size blade, good overall knife
Spyderco Delica - nice every day carry
SOG Trident - very practical knife
Benchmade Griptilian - very practical - looks nice
CRKT M16 - smoothest action on any folder i own
Ka-Bar Mule - great value for money
I own all of these and have found them to be pretty reasonable and most likely in your price range.
Hope this helps. Sorry I have rambled but happy to discuss further if it is of interest.