The heck with that. When will we see G5 iPods?!
Just kidding.
The next bump for the iPod (color screen for all, 20g, 60g, 80g drives and a bump to probably 8 or 10g for the mini) should arrive around WWDC. This will also coincide with the release of Tiger and speed-bumped G5 desktops (2.3Ghz, 2.5 & 2.8) Also, speed-bumped and feature-bumped iMacs (bigger drives and better video and faster processors)
Speed-bumped PowerBooks should arrive in March. G5 PowerBooks will wait until MacWorld 2006
Mac Mini will get a speed-bump at the same time as the G4 PowerBooks.
eMac will go the way of Elvis by WWDC.
Phew! This is all speculation. I have nothing upon which to base this but my own expectations based on where we are now and my experience watching Apple schedule releases over the past few years. Feel free to flame.