All depends on what your using it for. I carry a Southern Grind Jackyl Pup (little fixed blade) on my belt. Why? It is small enough to not get in the way while I'm bending down, twisting or carrying things. It has a steel that is easy to resharpenen when needed, & stays sharp & takes whatever I throw at it with ease.
I also switched from my normal folding pocket knife to a Microtech Ultratech with the double edged blade. One side is a full serrated & the other side is a straight edge. I went with that style because you have double the blade. I cut alot of rope & thick plastic wrap & the serrations easily go through that. The straight edge part is my box opener, mail opener or whatever. Best of both worlds & a good, usable blade length. If I go out & dress fancy, I have a lightweight carbon fiber Southern Grind Spider Monkey for that. If I know I'm going out & need a good workhorse, I have a Zero Tolerance 0220 Anso that is sooooo smooth, for that day. If I have on my Pj's walking around my house, I carry a Benchmade Impel. If I need a BIG fixed blade for camping or backwoods stuff, I have a Spyderco Pygmy Warrior which is a phenomenon knife! I also carry my Benchmade 140. I have so many other smaller fixed blades & folders. It's just what fits your mood that day & what you think you'll need it for. Have many, plan ahead.