Here are my actual user folding knves, with a few words on each explaining why I favour them and what are their shortcomings, for your reference. Most have been reviewed or talked about previously by me as well as others.
Opinel No12 slim.
My carving knife, when nothing else works. Better for that than any of my standard kitchen knives. Used when I want really good slicer for carving, deboning etc.
Really light with a large, sharp and robust flexible blade.
Totally rubbish at cutting bread etc.
Cold Steel Kudu

Cheap (really cheap), large, easy to sharpen, interesting lock, light. I cannot think of a lighter folder with such a large blade. And the noise…. Solid enough blade, an excellent general picnic knife that is light enough to go in your pocket but large enough to cut bread, meat etc. The edge is not as thin as I would have liked (easy to adjust).
GEC Bullnose

Cheap for a GEC. Solid, O1 blade, does not rust too much (not too much aftertaste on food, compared with 1095), good walk and talk, looks utilitarian even in orange, steel liners. My larger traditional slipjoint.
I wish it was also available in SS
Opinel No8 Slim
Light, sharp, shiny, cuts as good as the standard 8 but looks sexier. The blade is short so it is not very flexible. Not as solid as the normal 8 though.
SRM 763, standard handles
My most popular hard use type knife. Spends most summer clipped to my shorts. Very good quality, sharp and tough blade, smooth, has a bottle opener.
Looks ugly and the blade is too thick for apples.
Queen Cutlery 51 trapper,D2, Derlin scales.
Bargain, if you find one get it. One of 36 made, by the old Queen.
D2 steel, very good finish, polished, excellent walk and talk, sexy looking. My most carried slipjoint, since I got it. I expected something bad based on the fact that it was made just before queen was sold and it was only $37, cheaper than the queen sodbuster and a lot better looking. Slim blades that cut well and derlin scales so dropping it is not a problem. I had to work on the blades but it is a Queen after all. Buy one, but be carefull as there are some 51 versions with 1095 steel too.
GEC Conductor, 440C 
Nice size, my most carried slipjoint before I got the Queen, solid, nice finished very nice walk and talk, light and classy looking. I bought it because it was small. Has stag scales so I was always carrying it in a pouch as I was worried about damaging it. More expensive than the Queen, though I cannot see why there is such a big price difference. The differences that I can see are the scales and the more solid and handmade feel of the GEC.
Rough Rider stockman, root wood scales. 
Really good, though the scales were a bit loose. Excellent walk and talk, hard wearing, small, nice looking, light 3 solid and sharp blades, no play, an excellent package, for when I feel like carrying something with blade variety but still small. The scales are as new despite being carried unprotected with keys.
Camillus 51 Barlow 1095 steel
My only used buy from the user list.
Old but with excellent walk and talk, feels good in the hand, no play really solid made knife. I sharpened the blades and they are lasting well despite whittling with them. The 1095 rusts and leaves an aftertaste really easily.
Buck mini toothpick.
All the knife I really need, unless I want to carve a roast. Came with loose scales, covered in green oxidation. I cleaned it and glued the scales back on and has been my discreet/light knife of choice since. Cuts well, solid.
Which are your most popular knives then?