Do the Ipods load/play standard MP3 files?
That's about all I play on it! The only thing that the iPod won't play is WMA files but iTunes will let you convert them to the MP3 or AAC format (provided the WMA file isn't DRM protected). But even in that situation, you can burn your protected WMAs to CD and then reburn them as MP3 or AAC (MP4).
The AAC songs you buy on iTunes have the same kind of protection but you can also get around them by burning them to CD and then re-ripping them (though you might lose a little sound quality doing that).
Currently Microsoft and Apple have a little war going on regarding WMA vs AAC. (What else is new)