Small digital recorder - experiences?

Have any of you used a small digital recorder that you are happy with? I need something fits into pocket nicely, records hopefully MP3 or some other compact format that directly plays on a PC. Goal is to record voice initially, not necessarily music, although thats an interesting option. Mike input option would be nice.

Ever tried using iPod for this purpose? Or some MP3 player?

Key are play back quality and ergonomics and small and many hours per battery set.

Thanks,
Art