I have been down this road so many times. I have carried a large locking folder for a while, I carried a Leatherman Wave for a while, I carried a SOG Powerlock for a while, carried a small locking folder for a while, I carried a small slipjoint for a while and I carried a few different SAKs for a while. I have also tried carrying both knife and multitool but that doesnt work at all for me and never has lasted more than about half a day. I don't usually carry stuff on my belt. Multitools go in my pocket 90% of the time. I just recently got a pocket clip for my Wave though and that works well too.
So, after going through all these different EDC blades/tools over the years, what would I choose? I would (and do) choose to carry only a single large locking folder. I dont work in a proffession that makes a multitool any more usufull to me than the avergae Joe so that is not a factor. While I realize that in the urban jungle that I am forced to live in there is much benefit to a multitool, I just cant seem to justify the extra weight and bulk. Multi tools have flimsy blades compared to my EDC folders (Sebenza and Ritter Grip most recently) and though the tools on the multitools are handy, they just arent deployed often enough to justify the extra weight and bulk. The Wave and SOG PL both weigh about twice what my Sebenza weighs and the Ritter Grip is even liter than the Sebenza. I like my pants comfortably loose in the waist and just dont like the extra weight pulling on them.