As a quick bit of background, the Delphi 8 Update 3 patch fixes the problem with .NET 1.1 SP1 and is binary incompatible with previous Delphi 8 versions. The Delphi 2005 Update 1 patch solves the most pressing issues with the RTM version of Delphi 2005 (most notably, memory leaks!).
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.