From NT/5.5 to 2000 or 2003?. Are you planning to upgrade from NT4/5.5 to Windows and Exchange 2000, or are you perhaps considering jumping all the way to 2003? Exchange 2003 offers many new benefits and features over Exchange 2000, as this Microsoft chart shows, however there may be a few more things to consider before you decide whether to become an early adopter or not.
It is worth remembering that Micrsoft have developed a number of new migration tools which should ease the move to 2003. … [MS Exchange Blog]