I used to be sold on MEPIS linux and I had good language support for western languages. I had tried Ubuntu, but it just didn't grab my attention at the time... HOWEVER, I started trying to get Korean to work with MEPIS and I failed miserably... IT NEVER WORKED RIGHT!
I had a computer that I wanted to give to my wife with linux on it and she is Korean.... sooooo I tried out Ubuntu. (7.04 at the time... I am now using 8.04). Ubuntu installed and ran perfectly with Korean support. That sold me on the distro right there!
Version 8.04 has improved tremendously!!! I had my computer installed without language support up front. I later wanted to add Korean support and it went so smooth. ALL I HAD TO DO was go to the SYSTEM / ADMINISTRATION / LANGUAGE SUPPORT and select the Korean Support and checked box for complex character input and BAM, it downloaded all the needed packages (with one exception) and I had 한굴 installed and working in every app!!! Even OpenOffice! (except Abiword... haven't figured out why it won't show the characters)
The package I FOUND i needed that wasn't installed was the SCIM-QT-Bridge package... Ubuntu is a Gnome desktop environment by default.
I needed it for those few QT based apps that I use (VirtualBox!!)
So, give it a shot if what you want is flawless language support.