Liquid Wrench or Graphite spray, depending on the application.
I like WD40 for cleaning up rusty stuff and "pushing" water out of wet mechanisms (like vice-grips left out in the rain); but for true "Lubrication": not so much.
In the dusty corners, I recall a reliable source telling me NOT to use WD40 on electrical contacts. It leaves a film that interferes with electrical conduction, thus making the contacts unreliable (I think this is temporary, but annoying nonetheless). Also, until it dries, WD40 can be highly flammable, so do not use it to do anything to the innards of a distributor (POP!! scratch one distributor cap)... first hand experience.
Further, I find that WD40 has a tendency to "dry out" joints, like maybe it dissolves what little lubricant may have been there. So, an oil will need to be applied later, anyway.
My preferred go to for easy lube where dirt wont be a problem is liquid wrench. It is also excellent for freeing rusty stuff. I've salvaged many "rusted up" tools with it. Much like WD40, however, I find that a true "lubricant" (like machine oil or grease) often needs to be applied not long after Liquid Wrench has done its job.
On things like open jackscrews and scissor jacks (think RV stabilizers), where dirt/grit attraction/retention is a problem, I like a graphite spray. It will stain concrete (and probably just about anything else), so use it somewhere you don't care about staining or put down some disposable sheeting under the treatment area.
I'm intrigued by the liquid film mentioned here...never heard of it...must check into that. Might be a good alternative to graphite.