The most powerful Xeon currently available, is the Penryn Xeon, featuring 12MB L2 cache, clocked at 3.2GHz, on a 1600MHz FSB. So far, Intel was really pushing Pro-oriented CPU vs. desktop CPUs, with Xeon getting the last technology development earlier than mass market CPUs. However, Intel just announced a future Core 2 Quad Core model (Extreme) which will have exactly the same specifications as the current high-end Xeon (US$ 1399).
However, only Xeon-dedicated motherboards can accept 2 CPUs, and we are still waiting for Apple to update the current Mac Pro line with the new high-end Penryn Xeon and faster motherboard.
The recently introduced Santa Rosa-based MacBook models feature an power improved USB2. Those models could deliver 1.1A from their USB2 port instead of the standard 500mA. Such feature can be really useful for powering USB2 peripherals, such as external HDs.
FireWire remains a much better solution to deliver power to an peripheral with 7W.
One of our French forum members, Aigle4, has decided to repair as well as modify the original water cooling system of his PMG5.
A step-by-step procedure (in French, but with many photos) is available from his personal website:
http://nysoyan.free.fr/Eaglefour/PowermacG5.html
Before:

After:
Those of you who have a Gmail account can now thank the Google engineers. Contrary to what their documentation
still states, chat functionality has finally been integrated with Safari. I didn't notice this until after the 10.4.11 system update, so I had figured the feat was due to the Apple engineers, but... not exactly, chat is working equally well in Safari 2 (although not in Safari 1). In addition to the speed increases of Safari 3.0.4, I must say that with this latest constraint lifted (I like to communicate with my contacts without having to use 3rd party tools), tonight, I can bid adieu to Firefox for good.