* Voice Recorder (Free) by Mamoru Tokashiki
In addition, you can set it to start on a timer without pressing record button and easily search your files by title and date.
* Tape-a-Talk Voice Recorder
The Pro Version allows you to do fast-forwar, cut/edit/repair file and add Home screen widget.
In a slightly noisy environment, the source close to the device sounds crisp. Highly recommend it for those who do adhoc recording.