<p>Ogg is free, and if your lawyers can take the license (you do have lawyers, right? mp3 has some restrictions for the lawyers to go over, and I assume the others do to), adding support is basicly free, just use their libraries. Anyone writing a PC program not supporting OGG is making a fairly stupid decision because it is so easy. OTOH, for devices sometimes space is an issue and you might have to make the decision to drop it. (Though there is a intiger only version of ogg so you might find you can use cheaper hardware if you only support ogg, and this might work to your advantage...)
Ogg may never gain much support, but it will always be around.