Just gonna add my two cents.
I carry two knives a work knife and a fighting knife. Reason being is I don't want to make concessions to get a combo tool.
Serrations are great for cutting rope, outside of this task they tend to make other chores harder. They don't sharpen easy and I can attest that they do indeed catch on clothing particularly jeans, and you will loose your knife or hurt your wrist if used for that activity. On top of all of that they really make mundane cutting tasks harder.
Plain edge blades are my preferred knife for all purposes. They cut most things easier and are sharped cheaper or easier if you can do your own. They make for better carry knives all in all.
Once that is squared away you might want to give a thought about the locking mechanism. I see far too many cheap knives with liner locks fail with catastrophic results (EMT-B). Don't get me wrong I like liner locks but if the piece of steel used to lock your blade open is just a thin sheet of scrap than you are a braver man than I. CRKT has a great little feature called the autolawks. That is a great idea and works well. A lot of reputable manufacturers will use steel that is at least 1/3 the thickness of the blade itself.
Steel only matters as much as you are willing to spend. If you have or are planning on getting a good sharpening system that 440A,C or even Aus-8 can be maintained. If sharpening is not your thing the exotic stuff will hold an edge for years before you need to pay someone to sharpen them. A word to the wise however, 154CM, VG-10 and CTS XHP require a well dressed diamond wheel to sharpen.
I think I read that you were heading out to pick up a spyderco but this is good info for anyone. Good luck and keep it sharp!