I know someone who uses and really likes the YN flashes, although I can't really say that I've been a fan. I can't remember which model I played with (might have been the 560) but it seemed pretty good and fairly reliable.
Personally, my choice for cheap manual power flashes would be the LumoPro stuff- the LP160 and LP120 which are powerful, responsive, reliable, easy to use and very cheap. Alternatively, something like a vivitar 285HV might work- I think the voltage on the newer versions is compatible with modern cameras, but you will have to check.
Of course, if you want TTL flash metering from a 1st part, don't need a lot of power, and you don't intend to ever use flash off camera, you could always just go with an SB400.