In the server world we have alot to thank AMD for. Long gone are the stupidly high prices for fast multi-cpu 64bit propriatry boxes.
If AMD had not come to market with dual core quad socket 64bit x86, I'd been currently having to justify spending £100,000+ for an Itanium/Power/Sparc processor based system.
Now I can come to the table with a £40,000 system with much better single threaded performance as well as keeping up with the above system in terms of users I can stick on the system. I can employ cheaper system administrators, because I can use Windows Server (quite a price premium for Unix admins).
Implementation times are shorter, because it's just quicker to get a windows box up and running compared to Unix.
I used to be a complete Unix advocate, and still like some of its features, but the reality these days is that windows server is just as stable, easier to administer and the hardware is cheaper.