There is NO REASON WHATSOEVER to make a window top-most if user has not explicitly requested so. And no application should make that sin.
Let's imagine a scenario in which your server temporarily refuses connection. Outlook detects that password/user-name fails and decides to ask you. Since this is so important it shows window in foreground as A FUCKING TOP-MOST window. You dismiss it with cancel in order to continue with your work. In three seconds FUCKING TOP-MOST window reappears and you click it away, again. And it appears again. And you dismiss it again. And you start writing something only to have that FUCKING TOP-MOST window steal focus again. Most viruses/worms/diseases I know are not annoying as much as Outlook 2010.
I believe that developer who implemented this should be forced to do team programming with whichever moron manager thought this was a good idea. And they should kick each other in balls every time window pops-up.