Wow, that's some really peculiar new models from Apple. We were ready to buy a new iMac, but the price increase and minor improvements (after nearly a year) decided not to bother.
The whole point of looking forward to Nehalem processors in the Mac Pro was the big jump in performance. I suspect Apple have largely negated that by making the base model quad core, and using a slower clock speed in the 8-core. At the same time they have increased the price. While it seems likely the quad core might offer some performance gains over the previous 2.8GHz 8-core model, I very much doubt it will be significant - and for the price hike I'd expect a LOT more.
I'm very happy I bought when I did - Feb 2008 Mac Pro.
And I'm still baffled about what the heck they're doing with their display line-up. The 24" LED displays - made specifically for the MacBook / MacBook Pro, with the magsafe connector etc, and now they've updated the desktop range the '24" notebook display' is the only option below the 30". Doesn't make any sense to me. Do they really think all Mac Pro owners will buy the 30" display?