I would go for the eval version. Eval version has all the packaged you'll need for great linux experience. Differences between the retail and eval versions are just minor, some commercial packages are missing and you wont have helpdesk-support from novell.
The OSS version is crippled in many ways and you have to add sources and update many things to get full functionality. The OSS doesn't have acrobat, flash, only a limited number of drivers, and the mp3-support is disabled (well atleast its not working out of the box) and so on...
When you install Suse, you can choose which environment to use KDE or GNOME.
Well if you want, you can install both or go just with textmode only...
And for the language support, you can pretty much select what ever you want.
I have never tried installing with different languages, but thats also possible.
There is also a live version floating around if you really want one.
Novell suse10 downloads - Eval and Live