i have tried at least 7-8 different flash memory based mp3 players and i highly recommend iRiver players. (i am currently using the iriver IFP-799)
it has very good battery life (799 has about 30-35hrs on a single AA batt.), built in mic, fm tuner, line in for recording any audio source, plays wma& ogg& mp3, once you flash the firmware to UMS version, you can use the player as a microdrive and do simple drag&drop.
plus, the player comes with case, armband, neckstrap, and a sennheiser earbud.
EDIT: another player that i recommend is Samsung flash based players. believe it or not, Samsung flash based mp3 players are just as good as iRiver ones. (their hdd based players suck big time though.)