This isn't a high-quality recording device. High bitrates won't give high quality recordings. If you have a really good external mike, you'll probably get better results, but if you're using the internal mike you're wasting your time and storage space. There is a recorder available, Maemo Recorder. It's plenty good enough for voice memos, and that's about all you can expect using the internal mike.
In my experience, even the cheapest, crappiest mics in the world will generally sound much better at higher sampling and bitrates than they do at 8bit/8khz.
I haven't tried this yet, (maybe it will be recording too much keyclicking).
But, it would make an interesting option for classroom / note-taking to use voice recording along with typing notes onscreen in some app w/ the iGo keyboard.
Then you can just fold it all up into your shirt pocket. (take THAT Macbook Air! )
Doubtful that the microphone installed in these things is worth recording at a highter bit rate.
I don't think there's anything wrong with the quality of the N800 microphone as mini-microphones go. It's not expensive these days to have a reasonably high-quality microphone, at least enough to benefit from a high sampling rate to pick up higher frequencies (Nyquist criterium - sampling frequency must be 2x the highest frequency you want to record). What's typically more expensive is a microphone designed for directional pickup and noise cancelling so that it records anything but noisy echoing distorted sound in a large room, and full bass frequency range below 150 Hz.
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