Midpack, man,
They're just rumors. I'm about 60% convinced that they're going to come true, but until then, don't sweat it dude.
If you go to the store, right now, and get an iPod, I don't believe that you will be dissatisfied. It's an excellent player (I bet you can tell that by my sig and avatar, eh?)
As far as will MC be compatible? I'm not with J River, but I can probably tell you with authority that there's no way to tell if it'll be compatible with the iPod v3 (which is what we're kind of calling it over at the 'lounge). Apple may take the opportunity to re-do the way the database is ran. The PC-compatible v3's may (according to rumor, that is) not even have firewire at all, but be USB2 only. Heck, maybe the v3 won't even show up as a removable disk anymore.
I guess what I'm trying to say is don't fret about rumors and don't fret about technology that may be introduced. In the tech game, you'll never win the "wait till they're done upgrading it" game. There'll always be something better around the corner.
MC and the iPod v1 and v2 work GREAT together.
To Steve, Jim, Matt, et al...
About the AAC thing...
Some of the rumors involve the iPod v3 may be able to playback more than just mp3. There's talk of OGG and AAC and MP3-Pro. I've never actually fiddled with these formats, but I was wondering... can MC9 work with them (rip, encode, etc) in its present incarnation?