And you can get a lot of stuff as
redistributable files. I have some .NET files and
some Service Packs that way, for emergencies.
You'd at least want to keep the SP3 redistributable
around for yourself. I think I have all four service
packs here, but a couple of them weren't downloaded
from trusted sources (weren't available at the time).
SP1a removes Java, from SP1. From SP1a, there is
no Microsoft Java in the install - you use Sun Java
instead if you actually needed it.