Regarding the PC World test, I don't doubt that the PCs are faster. But I do want to point out a few issues that might narrow the margin:
MS Word is a native Windows application. The Mac version will never be faster. It's designed for Windows, and as I understand it, Mac wrapper code is added before it's compiled for Mac OS X. Plus, it's a "Carbon" application, which means its framework is actually derrived from Mac OS 9 compatible APIs, not the native Mac OS X framework called "Cocoa".
Quake3 is also a Windows native application, although Carmack did keep testing it on multiple platforms. As I understand it from his .plan updates, the Mac version does not have the same level of tuning in the virtual machine that powers the bots and other changeable aspects of the game. The FPS numbers also seem quite low. I wonder if they were using the AltiVec optimized version? Many updates have been released to the Mac version of Quake3 in the past 2 years for G4/G5 CPUs.
Premiere 6 and Photoshop 7.0.1 are much more meaningful benchmarks. But again, Premiere has always been trash on Mac OS. (And heck, even version 6 sucked on Windows... but there is no Mac version of Premiere Pro 1.0 or 1.5 to compare with though). Maybe it would have been better to compare Premiere vs Final Cut Pro based on similar actions. (i.e., "scale clip to 50%, apply a gaussian blur, and do a 2 second wipe transition to another clip").
Photoshop 7.0.1 was the very first version of Photoshop released for the G5. On the Mac side, it's basicly Photoshop 7.0 plus a "G5 Accelerator" plugin. A much better test would be Photoshop CS 8.0.1. However I'm pretty sure the PC would still be faster.
There is also no note of the version of Mac OS X used. Based on machine specs (2 GHz G5 rather than 2.5 GHz, 2.2 GHz Opteron rather than 2.4 GHz, etc) I am guessing that this test is at least a year old. Mac OS X 10.3 has gone thru many substantial updates for G5 users. Some revisions were dogs for performance, others were much better. 10.3.4 and up have been great for G5 users in general from what I've read on the Mac forums.
I would like to see an updated version of this benchmark with numbers from UT2004 v.3339, Halo v.612 (1.5 on Mac, 1.06 on PC), and World of Warcraft 1.2. I would also like to see Mathematica and MATLAB benchmarks between the two platforms, as well as specific algorithms, such as libjpeg and libz to see how the two architectures compare on specific types of operations. Why not show some LAME encoding too? Where are the Maya 6 benchmarks? How about Lightwave? Protools audio mixing? Etc Etc Etc.
I like benchmarks, and I'm glad PC Magazine did indeed release these benchmarks... they inform and hopefully they also lit a fire under the butt of Apple and all of those that write software for Mac OS X (or port code from Windows to Mac).