1-Dos with DesqView 386/X, Qemm386 = fastest and most stable multitasking
2-Windows 2000 Professional = most stable and secure of NT flavors yet
3-Windows XP Professional = it's a good extension of 2000 for the most part, sercurity issues abound with new ones popping up each and everyday. The intergration of the web so deeply embedded into the OS is worry some on many account. Personally Microsoft has no right to know what I run on, where I go on the Web and Whom I happen to communicate with. It is an OS, not a Chain and Ball of servitude. I should not have to sec my system against Microsoft compiling personal information on me or anyone who has an account on my system, to sell to thrid parties.
Today in fact there was an email in my personal email box which stated it was from HyperIneractive and that they had been given my name, mailing address and email address by Microsoft for some study. I think it might be from my MSDN account that it came about from, haven't checked into it yet. That doesn't really matter, they shouldn't be allowed to do so without first asking me for permission.
anyway...

other than that, XP is good.
of course this is just my pov such as it is