> PS: Actually, the utf-8 display doesn't work 100% because Terminal.app
> displays my \lambda characters as two-columns-chars and Emacs doesn't 
> know
> about it, so the display gets confused and every once in a while a bit 
> of
> C-l is needed.

Again this comes from your settings. And there is another problem: 
since Terminal or xterm have only one font available you could miss 
some characters from this. The HELLO buffer shows in Terminal twice 
this:

	Greek (ελληνικά)                Γειά σας

because they're Lucida Sans Typewriter -- and it shows some extra 
scripts that GNU Emacs puts there: Amharic, Braille, Georgian, Lao, 
Tibetan, Tigrina, half Japanese. Hebrew, Thai, and Cyrillic are in the 
font too and visible, but not Arabic! It's right-to-left as Hebrew. (In 
xterm it looks worse: many hollow boxes and even more U+FEFF, a black 
square on one edge with a white question mark as in my screenshot.)

If you can't find the Character Palette, here is way to make it 
available: in System Preferences go to Locale (the UN flag), choose 
Keyboard Menu and click there 'Keyboard Menu in Menubar' plus choose 
from the window with the flags those keyboard layouts that you might 
like to use *and* Character Palette, Keyboard Layout. Now you can 
choose from the Menubar the 'Canadian Flag' menu which will have the 
Character Palette. Cmd-clicking you can drag/position a menu in the 
Menubar.

Have you tried to correct on Terminal's command line mis-spellings? 
C-d, C-t, C-w, Esc-BS ... work.

--
Greetings

   Pete