Sgian Dubh
David, my sharpening kit is pretty simple, and what I use depends where I'm working and what bits of my kit I have handy. When I go out doing contract or freelance work in other peoples' workshops I carry a combination oilstone. It doesn't take up much room and does the job, and it's generally all I need to get by ... well, not just get by, but be productive.

The only other stones I use on a regular basis are my ceramic stones in my own little workshop at home, a medium and a Spyderco ultrafine. Primarily because of the lack of oil in their use I do prefer the ceramic stones to the combination oilstone, but I can't be bothered hauling the whole ceramic stone caboodle about to different workplaces involving as it does the stone holder thing and the skooshy bottle of water - it's too fussy for me to bother with.

I can't be bothered with guides myself. I didn't learn to sharpen that way, and from what I've seen when people use them they're fiddly and slow, they get in the way quite often, and they can't be used on non-standard chisels, e.g., gouges and the like.

I know I've said the following before, but I'm in that group of woodworkers that operate on the 'Sharp'n'Go' principle, i.e., sharpening has to be quick because while you're sharpening you're not working wood, which doesn't at all diminish the importance of using sharp tools. There's nothing wrong if it takes you ten minutes, or even twenty minutes to sharpen a plane iron or a chisel, generally just so long as you're not involved in making a living as a woodworker, ha, ha. Slainte.