The Buck Vantage series is a good candidate for you.
Three available steels. However, if I'm carrying it with the clip, I am less concerned with the steel and more with the handle material. The Vantage Select is available with FRN or PaperStone handles. The FRN is smoother and therefore doesn't tear up the pocket fabric. The PaperStone is rougher. The Vantage Avid also has smooth handles, being made of Dymondwood (a synthetically stabilized and dyed wood), and the steel is upgraded to 13c26 Sandvik. The Vantage Pro has the S30V steel, but the handle is a very "grippy" (rough) G10. That stuff can really wear on the pocket fabric.
One nice thing about the Vantage design is that you can open it four different ways, three of them one-handed: 1) use the flipper and wrist-flick to snap it open, 2) use the thumb hole to open it one-handed, but without startling the more gentle souls near you, 3) hold the thumb hole pinched between thumb and finger and gently flip the handle down, and 4) use two hands.
My personal choice was (and is) the Vantage Avid. Smooth handle doesn't tear up my pocket, 13c26 Sandvik steel takes and holds a really nice edge. And I paid less than $50 for it. Actually, more like $35.
Although you noted that you don't care for assisted knives, I would still suggest having a look at the Kershaw Pack Rat. It also uses a Sandvik steel. Very nice and broadly useful blade shape. I make salads with mine. Tomatoes don't have a chance. Very light, very flat, rides in pocket well (I removed the pocket clip).
The spring bias the keeps it closed makes a safety unnecessary, and requires a little more energy to initiate the flip. Lock-up is solid.
And finally, if Kershaw is still making them, there's a version of the Vapor that has a flipper. And, of course, there's the Kershaw Chill. Oh, wait . . . doesn't the Kershaw Ener-G have a flipper?
