In terms of usability (not reliability or secure) I think Windows 95 was a big step, a big change. However, I think that so far, Windows 2008 has been not so insecure or open than previous boxes.
Of course, there is no perfect operating system, and I still prefer Linux for sure, but Windows 2008 is not bad. The main problem, Win2008 is a server Os, so users don't usually run it on their PCs.
Vista is crap! We are just replacing all our PCs with Win 7 because that. Slow, buggy, really bad. Even in terms of memory footprint, XP was better.
Now with Win 8, people probably won't be able to dual boot or install Linux! Thanks to a new way the MBR works; requires some type of encrpytion, so installing another Os won't work (that's what I've read, actually this morning via Zite)
Thanks Bill!
Ironically, I love MS-SQL, a Microsoft product.