This is not a hardware question. It is Microsoft Windows vs OS X (OS X kicks butt) and Microsoft Windows vs Linux (Linux kicks butt).
The issue that prompted this discussion is what kind of machines our developers ought to have to be most productive.
Bob is our die hard Mac user. Anecdotally, his Mac (almost 3 years old, Core Duo) seems to run circles around newer Windows machines with Core 2 Duo, when it comes to compiling our source code, running AWK and GREP, etc. But then again, all Mac users have that fanatic gleam in their eyes so we tended to discount this.
Then, I decided to replace my 3 year old Sony TZ laptop (Intel Centrino, 1G RAM) with a new souped up Sony TZ with 2G RAM and Core 2 Duo CPU, running Vista Business. The old one, about to be donated to charity, was re-imaged to run Ubuntu Linux. When we did a head-to-head test between these 2 machines (the test was a ground up recompile of all our source code), the old machine was 4x faster than the new one!
The smart guys up in Redmond appear to be the perfect antidote to Intel & Moore’s Law.