I wouldn't try CamStudio unless you really want to. It has lagging problems and most of that is because it can't record uncompressed. It has to use a codec to record, and generally, when using a codec, the game lags because it's busy encoding it and recording at the same time.
Hypercam 2 or 3 are pretty good. The latest hypercam 3 has a fix for sound lag, though it doesn't always solve the problem, it helps.