Trumpet oil and almond oil - works for me...
I'm a huge fan of Windlass swords; most of my sword collection is made up of MRL product. But my very first sword, which I received for my 13th birthday, was made by a local craftsman down in Baltimore (Baltimore Knife & Sword), purchased at their old shop before it burned down. The swordmaker (I think his name was Kerry Stagmeyer or something similar) recommended that I keep my sword oiled with trumpet valve oil, which is a very light oil that I have since used on every sword I own. In the 15 years since, I have had great results with it. With no more than a bi-annual application, my blades have remained entirely rust-free.
For wood or leather grips and scabbards, I am partial to almond oil, which was recommended to me for use on my practic chanter that I bought from a bagpipe maker in Edinburgh. It has the same effect on wood and leather sword parts that it does on the chanter; prevents drying and cracking, and is non-toxic. The only problem is that I have trouble finding it in the states, though it is available from any chemist in the U.K., so whenever I go back to Scotland I stock up on it. Again, a bi-annual application is more than sufficient.