One of the things that I enjoy is putting together combinations of knives that work well together. Here are some of my favorites:
Leatherman Wave + Benchmade 160 Tether Knife : The Wave IMHO is still one of the best do-it-all multitools out there. The Benchmade supplements it well by providing a flat, light, fixed blade knife for pocket carry. It has a useful blade shape and is made from GIN-1, which I really like.
Leatherman Juice S2 + Spyderco Rescue Jr : I've mentioned these knives many times in previous threads, but they really work well for me, especially together. Between the two, they give me light-duty pliers and wire cutters, a few common screwdrivers, plain edge blade and scissors, and a lightweight, locking, serrated blade. My favorite for EDC.
Victorinox Tinker + Spyderco Ladybug II : Lightweight, versatile combination when a bulkier, heavier multitool is not needed. The Tinker provides a few tools, and the small spearpoint blade is perfect for liberating donuts from their boxes...

The Ladybug II can cut some tougher materials than the plain-edge blades. One of my weekend favorites.
Victorinox Pioneer + Spyderco Rescue Jr : I really like the single-layer, one-blade Pioneer. Sturdy, flat, lightweight, and easy to sharpen. Paired up with the Rescue Jr, this is one of my favorites when I don't need a bunch of extra tools.