AFAIK, normal ipods are pretty well supported, if not by Rhythmbox then by Songbird which is made by Mozilla http://www.getsongbird.com/system-requirements.php
and can have their songs put on with them. I guess the best thing to do is try it before you install or get rid of Vista, if it works OK then go ahead! Otherwise if it doesn't work, if you have an XP of Vista install disk around you could always install it into a VirtualBox so you can use iTunes and still not have to use Windows 99% of the time.
Ipod touch's and iPhones cannot be used without Jailbreaking them although it has been reported that Songbird may support them properly in the future.
EDIT: If you want to install Songbird, download it from the above link and install it using this guide: http://www.ubuntugeek.com/install-songb ... buntu.html
you just need to change the name of the file to the name of the one you downloaded as that describes how to install an older version. Also, the "tar" command needs to be run with sudo.
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