the discussion also on this board that I started titled "Suggestions for a 1GB flash player." There are a couple models noted in there that I think are considered in the top 5. I'm not sure of their voice capacities though, as that's not something I've been researching.
i am looking for a flash MP3 player that has atleast 64kbps voice recording and 1GB of memory.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic