Pericles, interesting points again:
"I do think that the majority of Corporate Users are basically computer illiterate."
LOL, very true. However, at least in the last major organization I worked in, it's spyware/trojans, most installed through IE, that caused the most serious issues. In terms of the nitty gritty of networking, it all comes down to if the OS will run the app you need. Wine will only take you so far in Linux.
However, it's becoming increasingly obvious that the direction windows is moving in is not in fact the direction corporations need, the more consumer bloat they put in, the more stuff there is to manage. There is a reason that city and country governments are starting to use Open source more and more. And companies. This year is a turning point in that process. My guess is that in most organizations, given that printing works, a clean linux desktop will do the job quite well now for maybe 90% of the users, the ones who do the same thing everyday and don't need to be changing the system all the time. You already see this in XP, sp 2 had to include many more security configuration options, most of which are needed to shutdown the newest security holes, usb memory sticks for example being only one. The skill level required to put out an even half-way secure windows system is rising, not falling. Whereas the skill level required to put out a reasonably secure linux desktop is probably less now than last year.
Not to mention some amazingly powerful tools you can use with linux in terms of managing remote desktops, much cleaner than that xp thing that fully exposes the machine to network level attack. But that goes off topic.
Re desktop search on the corporate level, not in the way either ms or google are envisioning it. A major security firm has already explicitly stated that no large organization should permit google desktop search to be installed due to serious security concerns, which I guess aren't interesting enough to the google people to think about, but which are very interesting to crackers and security professionals. There is absolutely no historical precedent that would lead you to conclude that these will be anything other than permanently insecure holes in the system, just like IE is.
The days of the constantly expanding fat client on the corporate network are numbered, it's getting absurd. MS knows this too, but they can't pull out of the path they are following, it's the only way they know. Imagine having a company of people used to things like multiple desktop workspaces for example. Or calling tech support and having their box fixed online in real time.