At initial install it's always wise to cancel the post-installer that starts after install, and apply
one of the most recent service packs (N or N-1). Given the trouble others have been having
with 10sp2 you might want to wait on sp2 deployment and just install 10sp1.
You do not ever need to apply multiple service packs, since, by definition, they are always
cumulative (spN always includes the fixes of sp1...sp[N-1]).
At ArcSDE 10 and higher, the upgrade process is done through ArcCatalog (if you have any
geodatabase functionality in use). In this case, you would need a 32-bit Oracle client on
the Catalog upgrade host for Direct Connect (which is required for upgrade).
- V