I have a tubus rack, and have used it for commuting daily for over 4 years now - it works great. There is a second set of rails below the deck which helps to lower the centre of gravity of your load. The fittings are fairly adjustable, and should be able to mount to pretty much any bike with the proper braze-ons. I think that the Kona JTS has braze-ons for a rack.

I use several different panniers for different things. The most common one that I use is an Arkel BUG. The Arkel BUG can be worn as a backpack (it has straps that fold up inside), but I rarely do that. It usually carries my work clothes, lunch and misc other stuff. I also have an Arkel briefcase pannier which I use when I am bringing work home with myself. And others that are used less often.