the question about what small flash to get for camera X comes up quite frequently, thus I wanted to share my experience:
for "serious" flash use, ie when I know I will use a flash for the majority of shots, like an event or something like that I bring my big Metz 40 with SCA adapter with me. But if I don't know, or when travelling, I wanted something smaller. I investigated a few options already when I had a Ricoh GXR and finally bought the small Metz 20 C-2
it has only 4 settings: off - M - 2.8 - 5.6.
On the back it has a classic iso/distance/f-stop diagram
Also, it has a locking lever, a tilting head (for bouncing off the ceiling), a small thyristor sensor in front and a PC sync plug.
So far it works wonderfully well. Set the camera to ISO 160, the lens to f2.8, the shutter speed to 1/250, the flash to f2.8 and off you go. As long as you are within the distance that is indicated on the table on the back of the flash, it works great. Even bouncing works, although with reduced range, of course. If you respect the possibilities of this little two battery gun, it exposes very well and fills the role as a cheap, small travel companion very very well.