I mostly use the AAC format (.m4a) when I encode my CDs these days. I've done enough A/B testing to determine that (at least to me) they sound enough better to be worth using.
I may post things here in .m4a format. This means that iPods are pretty much the only portable that can play them. Plus, it's possible that there are people whose software might not handle the format. Most players have plugins or some sort of method for playing .m4a files, at least.
Would there be massive outcry if I were to post music in .m4a format? I'm inclined to go ahead and do so, but if it would be WAY TOO ANNOYING, I'd go to the trouble of digging out CDs and re-encoding them. It would take longer, since I couldn't just upload what's on my laptop now, but for you, my beloved readers, I would do this thing.
Currently considering for upcoming posts: Shriekback, I Start Counting, A.C.Marias, You Shriek, and some others. Any requests? (I think I Start Counting will be next.) Plus, special guest posters Joe and Nik have accounts, whenever they feel like posting anything.
Let me know...