While working on a “community” PC at work, I noticed that several language packs were installed (along with all their updates).  While there is nothing inherently wrong with this, they can take up a lot of hard disk space and will unnecessarily install patches for languages we just don’t use.  This KB article contains the details about language packs. Here’s a quick tutorial that should guide you through the process of removing unwanted language packs for Windows Vista (taken from the KB article):

How to remove a language pack

1. Click Start , and then click Control Panel.
2. In Control Panel, click Clock, Language, and Region, click Regional and Language Options, and then click Change display language.
3. On the Keyboard and Languages tab, click Install/uninstall languages under Display language. If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
4. In Choose to install or remove languages, click Remove languages.
5. Under Select the languages that you want to remove, select the language that you want to remove, and then click Next.
6. Click the language that you want to remove, and then click Remove.

The only downside I’ve found is that you can only remove one language pack at a time; though the user interface teases you with a check box list of languages to be removed.  If you select multiple language packs and then click “Remove”, the first item selected will be removed, but all subsequent packs are left installed.  After each is removed, a reboot is required.