TYPO3 Core

which settings do you use for:
config.renderCharset
config.metaCharset

and BE->forceCharset in the install tool?
do you use tidy?

config.renderCharset
config.metaCharset
Both not explicit set.

[BE][forceCharset]
Not explicit set, left empty.

[FE][tidy] = 0

what Collation do you use in your db?

PHP-My-Admin outputs:
MySQL charset: UTF-8 Unicode (utf8)
MySQL connection collation: utf8_general_ci

If you mean what collation php uses to communicate with the DB i can server the information not before tomorrow (I don't have access to the typo3installation from here).
[edit]Didn't find any information about that in the phpinfo().
What information do you exactly want?[/edit]

Please let me know if you need more information.

Works fine for me. Cannot confirm. See, for example, http://accio.lv/ru/ or http://www.lgla.lv/. they are both in UTF-8 and have non-english characters.

I think this is a browser issue. Looks like it does not recognize encoding headers properly.

I had the same problem, and put following lines into the configfile for MySQL to solve it:

character-set-server = utf8
collation-server = utf8_unicode_ci

Think, in some kind that's what Adrian wrote.
Now I only have Problems to save template-files with german umlauts (in comments)

My second problem disappeard after correcting my setup in localconf.
Please read http://bugs.typo3.org/view.php?id=3547