of thoes you mentioned, i'd go with skyline, drifter, or leek, in that order, unless something particular about each draws you more to one or the other.
why? skyline has been a forum favorite for "bang for the buck" knives. it has a solid size and no funky recurves that could make sharpening difficult. heck, for $50, buy two. daily carry and use one and then practice sharpening it without fear of ruining it, since you always have another. use the other for dressy occasions where you don't plan to use it at all, since it'll keep its pocket clip from getting all scratched up. like your EDC one will. i also find that scaled knives (rather than framelocks like the shallot and leek) are wider handled and therefore more comfortable to use.
Same thing with the drifter, buy two if you like.
the leek's drawback for a first knife is the AO, where if you're not comfortable handling yourself and your knife around people, it might become an issue. it does carry nice and thin and light and has a classy, less intimidating shape than, say the skyline.
one thing to remember is that the average cell phone weighs about 4.5 oz, which is more than a lot of people like to have in their knives, but it's about what i prefer. i don't want some featherweight handle. plus, when it's clipped to your pocket, it isn't really as noticable a weight as a cell phone hanging in the bottom your pocket.
now, i didn't pick any spydercos because of personal preference. i prefer my CRKT and my kershaws over the basic design of spydies.
however, like most kershaws, you pretty much can't go wrong with any spyderco if you like that style, where CRKT is hit and miss.