Naaah, just Leopard (MacOS 10.5)
I’ve used Linux before, and quite frankly, the only reason why I don’t use it today is for the lack of suppport for most main-stream apps and hardware. For example, my Lexmark Z65 printer wasn’t supported. Nor is my beloved World of Warcraft. I am a computer nerd but even I had issues with compiling software and installing it…not to mention issues with un-installing and folder permissions. I wish Linux was more user friendly past the initial system install. Right now, I’m using XP and just recently got rid of my MAC for space issues.
Support for more than three hardware configurations. 
I’ve not heard anything about Vista that would convince me to switch. If I ever feel the need to upgrade from XP, it will probably be to some Linux, assuming Linux continues to improve.
Well, Linux has already overtaken Apple in market share, but I do agree that is will take awhile for it to make significant inroads against Windows on the Desktop.
I’m not sure how one would tally up “market share” of a free OS like Linux: it can be distributed in any of a zillion unrestricted methods, ranging from downloading Joe’s Wonderful Build from joeswebsite.com to purchasing a copy of Red Had on CD to using the CD in the plastic folder in back of Susan’s Guide to Linux Servers to snagging a help-yourself home-burned CD from an immense pile at LocalLinuxUsersGroup at the monthly meeting. I could easily see the real number of new installs/acquisitions of copies of Linux eclipsing the install/acquisition rate of MacOS, but I don’t know how you’d document that. Most of it would fly under the radar, wouldn’t it?
Are you talking about installed user base? The MacOS is estimated at around 16%, (much higher than its market share, which is computed from OS purchases if I understand correctly). If Linux has an installed base that eclipses that, that leaves Windows in all its permutations with less than 68% of the installed base.
That’s nice to think about, but I’ve got my doubts.
For most users, the switch to Vista will simply be a compulsory part of upgrading to a new machine - OK, not truly compulsory, but for most Windows users, the fact that there’s a choice is irrelevant or unnoticed.
Seriously. It’s got to be easier and cheaper to just incorporate cygwin in a more official capacity.
Sure, Microsoft couldn’t do its usual “define the standard to be our format” that it likes to do, but does anybody think that they’re going to be able to dictate how a commandline shell works?