AAC - Apple Audio Codec?
No, that isn't what it stands for. AAC is a format from Dolby and is an open standard. So I don't know why manufactures would support WMA over AAC since you would end up being stuck with an Microsoft license and a sub-par audio codec.
I say if you don't want an iPod (why I don't know) you should start asking Creative, and everyone else to support AAC (as well as WMA if you want) instead of asking Apple to support WMA. I think its an easier battle to fight.
If you want more info on the AAC format including licensing, click here.
Also if your interested, Ogg Vorbis has some comparisons of the audio formats.