One of those knives is without a doubt my first Spyderco, the original Native LW.

(I'll have to upload my own pic later)
While I have moved away from smaller knives, the ergonomics of this knife made such an impression on me that I've been following the basic formula for over a decade now. I still prefer designs with no thumb ramp, I still love the blade shape and it is a big reason I like lowered blade tips and shallow bellies, and about the only thing I've moved away from are finger choils but that's more with full size knives and I still want them on models in this smaller size range.
I would buy a "throwback edition" of the Native 5 with that same swedge and hollow grind in a heartbeat.
I know there was already a hollow grind version but it's gotta be the total package, I want the swedge and serrations. I would really love to see that FRN pattern again, but that would require expensive molds, so maybe machined in G10?
Anyway, I'd say the second most influential model for me has to be the Military.

This was the model that really opened my eyes to the advantages of carrying larger knives. For most of my life I stuck with 3 inch or smaller knives, mostly because it was beat into my head as a kid that generally that was what was legal and safe to carry. Once I got older and understood the laws better I gave this knife a try and it really shook up my preferences.
Besides the size of it, this is the model that made me aware of lowered blade angles and the benefits of full grip knives (I spent most of my life getting by with 3 finger grips). This knife taught me that big knives don't have to be heavy and cumbersome and can be a "carry and forget" situation.
So what are yours? Really give this some thought, because ironically enough those are two models that I don't even carry much these days, so this isn't necessarily about "what are your favorites" because making an impression on you doesn't automatically mean that something is your favorite. This topic could even include negative experiences where you hated a design so much that you stopped buying models that included a particular feature. What models have the features that have most impacted your preferences?