I'm thinking of picking one up and would like to know which is the best.  The two biggest factors for me would be video/audio quality and the video/audio formats supported.  I looked on wikipedia and noticed that the two systems I was already considering, Zune 80 and Ipod Touch, don't support DivX or Xvid.  Anyways any suggestions would be appreciated :)

psp

Creative Zens are great.

@leo-j

Does it support DivX and Xvid out of the box or do I have to flash it with non-official firmware?

Well let me check.

I notice they have DivX and Xvid support out of the box.  Are they very picky about the bitrate, resolution, etc for those formats?

No it does not supports Divx. Just checked by downloading a vid from my ps3 (divx vid)to my psp.

Now that you can transfer Blu-Ray (and probably DVD too ) movies from the PS3 to the PSP I guess PSP is definitely a contender .Its screen is great thats for sure .

Toshiba's Gigabeat series is pretty highly acclaimed. I almost bought one but picked up a Zune instead (I really like mine). I didn't buy an ipod based off word of mouth and my 3 brother hate of itunes (even though they own ipods and like the hardware).

The Creative Zen line of portable media players are the best I think.