I am used to installing the Service Pack on SQL Server and ALSO I am used to installing the Service Pack on my XP box.
==> BUT when I install the Service Pack on my XP box, I select ONLY client tools.
==> I don't want to install SQL Engine, DATABASE, etc ... on my XP box
I think the developer is wright.
When you install SP2 on your HP box, some bug with Management Studio are going to be fixed
(ex.: bug with Maintenance Plan)
If developper need to work in Management Studio, it is a good idea to install CLIENT TOOLS ONLY of SP2 on XP box for developper that need it.