If you don't know yet, MS Arial Unicode (with the full range of Unicode 2.1 standard characters) is available as a free font from
 
http://officeupdate.microsoft.com/2000/downloadDetails/aruniupd.htm
 
It's several times larger than Lucida Sans Unicode (a 23 MB TTF, downloaded as a self-extracting EXE file of 14 MB), but it contains 40 000 characters.
 
Piotr