DejaVu fonts are freely available from the DejaVu project page. Although it has the same problems with placement and spacing of diacritics as Verajja (unsurprisingly ) ), it's a very clear font, and its Book variant promises well as a general-purpose Unicode font. Verajja, other fonts supporting Vietnamese (including Gentium Alt) and fonts designed for Indic languages are available freely from here. Dejavu will be packaged with major distributions such as Debian (soon to be released with support for Vietnamese, for the very first time!). Verajja, which will soon be included in the free font Dejavu.Han Nom fonts, for the ancient Chinese-based writing system.

vn.net does have these Unicode fonts designed for Vietnamese: (Please contact me if you can't find them, and I may be able to send them to you.). It's one of a group of beautiful 'designed-for-Vietnamese' Unicode fonts which I can't find anymore on vn.net.

Vu Phu Tho shows you how combined diacritics should be displayed.

I use it as my default font, because it handles Vietnamese (and many other languages) so well, even though I have many 'designed-for-Vietnamese' fonts.

Lucida Grande, default Unicode font in Mac OSX.

Comparing Unicode fonts for Vietnamese Việt ngữĬlick on each font-name link to see font samples of several Unicode fonts, shown in the Font Book application from Mac OSX (it makes it really easy to manage your fonts).

Vietnamese words special font