The best of all time mp3 player i've owned has to be my Iriver H10. I've been through the zen micro photo, nano, ipod video, and a bunch of flash players and my H10 has provided the best sound quality and ease of use.
Ive gone like a week and a half without recharging it, of course, that was only with light use, but still. I cant get about 14-15 hours of audio only use out of it before it either dies or gets pretty close to dieing. For video i usually turn down the screen brightness to conserve battery life, and i get about 3-3.5 hours of life before it dies, with the LCD at full brightness ill get about 1.5-2.5 hours before the battery gives out. When i play games on it (mostly tetris) with a podcast or whatever playing at the same time ill get like 5 hours at half brightness.
If I ever get an ipod that would be for putting Linux on it and showing off.
I wish i could put linux on my zen, that would be cool.
For me, the best player was ZEN VISION M. I have been thru ZEN Micro H340 from iRIVER and RIO CARBON. I actually liked them all, RIO for the design, H340 for mic input, and ZEN Micro for its EQ and context menus respectively. When I got it the Micro looked actually attractive, with time this became relative and questionable - so I got ZEN Vision M.
This works straight without any hassle on any PC with XP and WMP
So there is no trouble getting music from friends. Works with Rhapsody and podcasts. Interface is very good (context menu, again, this is very good), screen is the best you can get for the money. Battery life is decent as well, I think it is about 15 hours, I charge it once a week, never bothered to measure, so might be wrong here. No complaints about sound quality. I tweak sound with EQ sometimes and the fact you can customize EQ is another point for zen.
As for video - it plays back divx and xvid files - I do not watch movies on it though, really, they look so much better even on my 22 incher