What is your favorite EDC?

Looking for the perfect every day carry knife (EDC) can be somewhat like choosing a pair of pants.  Everybody is looking for a fit that is comfortable and looks good.  When you go out to buy a new EDC knife, here are my ideas of a few things to focus in on. 
First, make sure you get the right size.  Just like a pair of jeans, if you get the wrong size, things will just not be right.  As you think about what you need your EDC for, what is the largest size blade you need, and what is the smallest size blade you can function with.  If you are going to just be opening boxes–a short Cali legal size blade (under 2″) will most likely be perfect for you.  If you are going to do some heavy duty, large scale cutting–you need to get a bigger blade.  By deciding the right size blade for your needs, you will immediately eliminate a whole bunch of knives from the discussion.  The last time I was deciding on a new EDC–about a month ago–I realized that for most of my needs, a small blade was preferable because it gets the jobs I need done as well as not taking up tons of real estate in my pocket.
Next, you should decide about blade material.  Do you want to step up to a nice, high quality steel blade like an S30V?  The different steel qualities will make a difference in how often you need to sharpen your blade as well as how sharp it will stay.  Here is a quick, down and dirty guide to blade steels:

S30V:  American made premium quality stainless steel created specifically for knife blades.  Powder made steel with extremely high corrosion resistance and keeps an edge.
154CM: American made premium quality stainless steel developed for industrial applications but used by many knife makers.  High corrosion resistance, high edge strength and ability to keep an edge.
D2:  Air hardened tool steel which serves for hard use situations.  Good corrosion resistance and very high in durability.
440C:  High chromium stainless steel with a good balance of corrosion resistance and hardness.  Takes an edge fairly easy.  Less expensive.
AUS8:  Japanese made high chromium and medium carbon stainless which gives a nice balance of corrosion resistance, strength and durability, and sharpness.  Used by many different knife manufacturers. 
8Cr14MoV:  Chinese made steel with similar characteristics to AUS8–used often for it’s value price. 
1095:  Steel used primarily for heavy usage.  Easy to resharpen and great for field work (outdoor heavy use).  Will rust over time and must be maintained.

Of course, there are a much wider variety of steels than those I listed briefly here.  These are just some of the more commonly used steels and should get you started.  If price isn’t an object for your EDC decision–I would bump up to S30V, 154CM, or D2 depending on what I will be using my knife for. 
Next step in choosing an EDC knife is to determining handle material.  There are an amazing number of different materials that you can pick from.  Some of the most common are 6061T6 aircraft aluminum, stainless steel, G10, micarta, or almost any combination of these materials.  Many knife manufacturers will produce a knife with a 6061 T6 or a stainless steel frame and then top off the handle with some type of overlay or inlay including such materials as carbon fiber, different rare and common woods, G-10, various types of micarta, or nearly any other material known to man.  The biggest thing for me, when choosing an EDC is to make sure the frame is built from material that will stand up to my level of use.  I am hard on my knives and so I prefer to get a 6061 T6 handle.  The other, possibly even more critical part of choosing a handle is to make sure it is COMFORTABLE in your hand.  If it doesn’t feel good–don’t get it. 
The next decision is to choose what type of locking mechanism you get in your knife.  There are several choices including automatic, linerlock, framelock, button lock and fixed blade to name just a few.  Part of this decision revolves also around how you want your knife to open.  Do you want a manual, a spring assist, an automatic or one that is always ready to go (a fixed blade)? 
Just for the record–my newest EDC is the Benchmade Impel Automatic Knife–a Lerch design.  Here is why I like it.  Small enough to barely feel in my pocket.  Auto open with a button lock.  Has a nice sliding safety right by the trigger button that makes it easy to use one handed if I need to.  A very nice aluminum handle with black G-10 inlay that provides a little extra grip when I need it.  And, it feels great in my hand.  The clip point blade is S30V steel with an incredibly hard black finish that has not scratched even a little with a month of fairly rigorous use. 
Now tell me what your EDC is and why?