There is kind of a workaround with iTunes in the form of iTuneMyWalkman (google it). It's a script which is really well written which allows the use of UMS (USB Mass Storage) players with iTunes. It's not exactly as plug&go as the iPod, but it's a passable substitute.
As well as the purpose it was written for (use iTunes with Sony Ericsson cellphones) you can use certain players from iRiver, iAudio X5/M5/M3, and many others both flash and hard disk. Problem is none of them ultimately hold a candle up to the iPod.
Newer Creatives are MTP so will not work, you'll need XNJB which has a certain degree of 'iTunes Integration' which is extremely basic. Creatives are cheaper than iPods but it shows, even in the new Zen Vision M.