I'm a bit of a sharp-schmuck, apparently. I have the Sharpmaker, a Smith's guided set, some DMT plates, EP and a Kalamazoo belt, with a WEPS on the way.
I think the biggest thing I can think of when trying to define "best" would be that it depends on exactly what you want to accomplish, and what you will be using it for. Just your knives? Your knives and some of your buddies? Semi-pro or pro-level sharpening? Every requirement has it's own definition of 'best'. I tend to use my belt more than anything else, simply because it is so fast, and puts on a terrific convex edge. For more polished finishes or if you really like V-bevels, the WEPS or EP is going to be a good choice.
A lot of it depends on your budget as well, decent systems range from $30 or so for a good double-waterstone or a Lansky guided system, up to $4k or so for a top-of-the-line Baldor knife-maker's grinder. If I had to keep just one, it would probably be the belt for it's massive versatility.