I have just had an interesting and illuminating (to me) experience.  I installed Ubuntu Linux on my old Thinkpad, and after a few days using it my thoughts re: Microsoft and Linux desktops are...MS needs to be afraid - VERY afraid.  

Back when I worked at MS, shortly before I left in 2000, I had a (very) brief discussion with CEO Steve Ballmer about Linux in the enterprise.   HP and IBM were just edging into endorsing it at that time, and I told him "watch out, because when it comes, it will be unstoppable."   He was concerned, but I doubt he listened, no-one else I tried to talk to about it listened.  Well, that was then.  The enterprise is all going to Linux.  IBM and HP and others have made a HUGE business selling Linux servers, and Dell has just started selling Linux desktops and notebooks.   The desktop revolution is coming.

Here is my experience:  I had a perfectly good IBM Thinkpad A21m notebook.  It was unusably slow running XP SP2.  18gb hard drive, 192mb of memory, 800mhz P-III.  A few months ago I replaced it with a new HP notebook that came with Vista.   Its fine, works great, but to DO that it has a dual-core 1.8ghz AMD Turion processor and 2GB of memory.  Its snappy, but not what I would call blazingly fast.  So, the Thinkpad went on the shelf for a while.  

Being retired and curious (I worked on Unix systems for years before joining MS) I looked around for a good Linux desktop distro to install on the old Thinkpad and after some research settled on Ubuntu, which is based on Debian Linux.  I downloaded and burned the install CD image and put in on the old machine.  It works GREAT.  Even with the limited memory performance is acceptable.  It comes with the Gnome desktop,  Firefox, OpenOffice.Org 2.2, Evolution for mail and calendaring and SAMBA for integrating with Windows networks.  I got it running in an afternoon.  It's FREE.  If you want support, you can get it, and the community support is excellent.

I added OpenProj for project management and a few other more geeky apps for my own use, also all free.

If I didn't have such a heavy investment in MS software and file types, I'd convert ALL my systems.

I have Visual Studio 2005 and Office 2007 and both products are so bloated and over-featured they are almost unusable.  I like them alright now that I know how to get the important stuff done, but both were radical departures from their predecessors, and were not "Better" in any way I could relate to, just "different", for no apparent reason.  The biggest single thing I learned was to turn off most of the so-called "help".  The learning curve was steep, amazing to me being a computer professional with years of experience using MS products.    Same deal with Vista.  The Aero shell is pretty, but so what?  The old XP shell worked just fine, thanks.

Microsoft needs to make some stuff that just works, that doesn't cost a freakin' fortune, and that doesn't require the fastest, most resource-rich PCs on the planet to run.  Otherwise, its over.   Heck, it may ALREADY be over.