Someone by the name of UNIXGEEK posted an AppleScript a while ago at Mac Geekery that changes Mac OS X 10.4 Tiger's keyboard layout to play nicely with a Windows keyboard. To be specific: the Command and Option keys are switched on a Windows keyboard (as the Windows key and Alt, respectively), so this script simply changes the layout on Tiger so your non-Apple keyboard still feels like home (sorry pre-Tiger users, Apple only introduced the ability to tinker with keyboard layouts in 10.4). If you aren't a fan of Apple's stock Pro keyboard or the MacBook/Pro 'boards, this script is for you. However, the script at Mac Geekery has a few errors in it, and Engadget's Ryan Block trudged through the post's discussions to make the proper edits to the script, and posted a fixed copy for everyone's benefit (download it from us, not Ryan. We don't wanna hit him with the TUAW effect).
As a side note, I think it's funny how attached people can get to one keyboard or another. I'm slowly getting used to this MacBook keyboard, though I've been a die-hard lover of the PowerBook/MacBook Pro's tight and low-travel keys since I've owned one for the last 4 years. Ultimately though, I dislike most keyboards because I used to own an ergonomic - y'know the funny looking split ones? - and that was absolutely killer for both teaching myself better typing habits and making sure I don't get carpal tunnel. The only ergonomic keyboards I can find in stores (since you gotta get your hands on those to really get a feel for 'em) these days are Microsoft's and, while I love their Intellimouse Explorers, their ergonomic keyboards' construction just doesn't feel up to par, and there's far too much needless travel in their keys.
But I digress (a lot) - if you're using a non-Apple keyboard on a Mac, enjoy this script for easily swapping the keyboard layout for your Mac computing pleasure.