Ah, this reminds me of the old days with the then new PowerPC. My old trusty Quadra 660AV was useful for some time after the new PowerMacs came out - in fact, it was BETTER than the new PowerMacs for some time. I'm sure that won't happen this time. Does anyone remember how Office for the Mac ran like a dog on the PowerPC? I'm talking 2 - 3 minutes to boot Word. Many suggested it was done purposely by the evil one, because everything else ran fine. However, he is our friend now right? Especially since Macs will be using the same processor his OS runs on? Also, they didn't Have Jobs at that time. It was a bad time for Macs. I sure do hope we don't have to deal with "fat" versions and all that back when the PPC came out.
Any way, I am perfectly happy with a somewhat outdated G4 DP 1 GHZ, and I do a lot of video editing in FCP, sound editing, general writing and office type stuff... It is still a fast machine and I have more than enough apps to keep me happy (except a home drafting/design program...). I'd say go for it if you really need a new computer, but don't go top of the line or $$$ - wait for price drops on mid level models. I think the middle level is always the best buy for the long term. That's why I didn't spend $1000 more for a G4 DP 1.25 GHz when I got my DP 1 Ghz, or the same situation when I bought my G4 450 over a G4 500.