I own a Creative Zen Vision:m and you can highlight an artist and click play and play all songs by that artist, or do the same by album, but I don't know of anything that does what you want. The Archos 204 displays music by folders like windows explorer, but I don't know if you can skip through entire folders during playback by pressing next.
Let's say I have unlimited resources :-). I can't find an mp3 player that will allow me to play by folders like car in dash mp3 players. I want to click an up button - it STARTS PLAYING the previous folder, I click the down button it STARTS PLAYING the next folder. I do not want to click, see a list then choose and click select.
Do you know such player?