I have a creative nano plus, its somewhat old now but I do love it to pieces. I also like Creative, in my opinion they are the people to go to for sound quality.
My current player is somewhat broken now, but Creative havent released anything Im interested in recently (like: I dont want a video player), so I havent looked at replacing it. I am starting to be tempted into buying a nice phone and using that. I am unlikely to be in any situation where 'quality' audio is required - often I listen to my music on the bus or when walking somewhere. The background noise just makes quality pointless.
Factors I consider when looking at mp3 players..
Battery life,
Must be solid state,
Screen has to be big enough to display all the ID3 information but not so big that battery life suffers hugely,
Capacity,
I dont like internal batteries, I prefer to use AAAs, but this is rare nowadays.