I have a D60, 10D and a 20D. I was thinking about the upgrade of the 1D MII then I herd about the 30D. Just when you think you know what is the right way to go Canon throws in a twist.
If you feel the need to move to a new body, in your situation I'd move to a 1-series, probably 1Dmk2. 20D vs 1DmkI aside, if you choose not to go to a 1Dmk2, maybe get 2x 20D. The 30D isn't enough of an improvement over the 20D imho. It's more for people going from d30,d60,10d,300d, or 350d.