If it's going to go in the bottom of my pocket I like a really thin body knife, but I really prefer one with a clip to stay at the top of my pocket. Easy access and I have enough stuff in the my pockets already. I have a benchmade mini grip and a case toothpick
Zero Tolerance 0350 (tiger stripe blade optional). The sturdiest folder around, IMHO. Forgot to mention this knife has a speed assist opening - not a switchblade, though. Can be opened no problem with a gloved hand and is light enough to be worn with slacks.