Setup a network for me where I can login from any machine as my user, have access to the Adobe Creative Suite, a shared exchange like outlook system, easy to maintain network config, iTunes, access to several shared printers, and maintain it at the same cost as our current Windows network and I will say that I won't go back to M$ 
i used to use windows 2003 on my servers, i ended un banging my head against wall and knocking myself unconcios once due to windows 2003 i had these problems:
on my first mail server install i forgot to make a postmaster account, so 1 bad mail made a never ending loop of mails and errors attempting to goto postmaster:
error
[email protected] does not exist, sending error to
[email protected] (this kept looping till it made 60gig of bad mail and i had to re install
on my second attempt at setting up the mail server i did somthing very stupid, i actually turned on logging under a windows server, people attempted to spam through the server so the error log got to 10gig, i had to reinstall again because the file was too big to delete
then i made a debian 3.1 mail server with postfix, i turned on logging, no problems, no problems at all
and about converting back:
NOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!111111111111oneoneoneoneonethese were just problems i had with mail server, sometime i will make a page with all the crap in windows server 2003
