In what order does one update when including Language Packs? With Service Packs? With Cumulative Updates? It used to be confusing. Now with 2010 it is straightforward.

Get the language packs:
http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=3411

now update your farm as desired.

1- SP SharePoint Server
2- Language packs
3- CU SharePoint Server
4- PS Config (on every box)

done.

NOTE: if you go and add a new language pack afterwards, you must reapply the CU as it may include updates for that language pack. (and rerun PSconfig again, of course)