Why do Ipod Touches keep filling up with "other" files?

don't even worry about album arts. they don't take that much space. besides they come within music files.

others are the space taken by data of apps, game progress, firmware temporary files. yeah, they keep adding up since your preferance stays in your device just in case you reinstall the app.

but mostly the high usage is due to duplicate music files in in media folder of ipod, that means there are two or more music files in your ipod for same song in pc. you don't see dupe in music app but it exists. try to delete the dupes from device by using ipod explorer like diskaid :

http://www.digidna.net/products/diskaid

as for recently deleted files, they aren't deleted from ipod permanently (just in case you try undeleting), a simple power off > power on might help

Its the poor people in the United states.. they're making it happen to you...

lol