... WHY?
Many people encourage to upgrade due to bigger stability, features, etc... which is ok.
Yet, there're a number of reasons to wait for BDS 2007(or whatever it'll be called).
First of all: everything that is in 2006 will be in 2007. Thus, you lose nothing waiting.
Secondly: you don't get dotNET 2.0, which is not really a huge loss, you know, but
actually ASP.NET 2.0 looks nice.
Thirdly: you'll get all the goodies of 2007, too.
Fourthly: if you wait a year, you'll have time to save money and buy Software Assurance, too, which will take BDS 2008 too to your door, for free.
Doesn't seem a bad deal, to me.
All in all, if you don't really need it, just wait. Many peers I know are doing just fine with Delphi 2005, so why upgrade now?
Regards,
Andrew