Alright, here's my commentary on the Canon announcements:
5D mkII
1) First of all, it's about damn time.
2) It looks like a 1Ds mkIII dumbed way way down, far more than the D700 is dumbed down from the D3.
3) 21MP sensor will do fine, but expect amateurs to complain about sharpness until they figure out how to deal with such high resolutions (this was a problem for pros when the D2x first hit the scene in 2004, but they've since learned the proper techniques to acheive maximum per-pixel sharpness).
4) Either the ISO25600 performance will look awful, or will be the same as the D3. If it's the same as the D3, it just goes to show that Canon is still king at making sensors work well at high ISO. If it's worse than the D3, then go figure, that's math for ya.
5) They've had three years to develop a successor to the 5D, and they're still using the same autofocus? Really? Shame, shame.
6) 3.9FPS is respectable for 21MP, but compared to the D300/D700/A900 it comes up short for sports use. And until Canon comes out with a sports-oriented camera to compete head-to-head against those cameras at this price point, don't bother telling me that it isn't meant for sports. If people spend over $1500 for a camera they have every right to expect it to be useful for more than just studio work.
7) It really one-ups Nikon on the video front, but for a camera that costs 2.5 times more it'd better. 1080p at 30fps with a stereo input jack is nice.
G10
With everyone clamoring for better noise performance in their compacts, why the heck would Canon put a fifteen megapixel sensor in one? Apparently someone missed the memo. Expect dynamic range and noise to be serious problems, like every other compact on the market. And everyone was really hoping that the G10 would break that mold.
EF 24mm f/1.4L USM
The introduction of this lens further highlights the fact that us Nikon users don't have the option of a fast wide prime. The AF-S 14-24mm f/2.8G is a great lens and all, but it isn't practical for everyday use.