A G5 version of the iMac/eMac would, of course, be great. However, given the heat issues with the G5, there'd have to be a complete redesign. So, I'm guessing that we'll see faster G4 versions.
However, if there's a redesign, I sincerely hope that they make the systems more expandable/future-proof. Yes, I love the all-in-one design. But...no other manufacturer produces a consumer line - an entire line of all non-pro systems - which is effectively non-expandable (yes, you can add RAM and an AirPort...). I'd really like to see a non-all-in-one, like the rebirth of the cube design which has been spoken of before. A cube - which at least has replaceable parts, even if it isn't truly expandable - coupled with your choice of monitors would be my ideal. All-in-one is nice, but surely they could design something that looks almost as good but won't be "obsolete" so quickly (yeah, I know Macs take a long time to be obsolete, but they can get dog slow very quickly...especially when underpowered at birth).
BTW, there's a part of the Bluetooth spec that would allow for wireless monitors. Don't know if it'll ever get used, but it's a cool thought...don't know what max res would be (probably minimal).