Anti-aliasing is a technique to hide the fact that the text is made up of
square pixels, which means without anti-aliasing, it will not generally look
crisp, especially when the font size and monitor resolution is low. Larger
text will be less affected. Personally, I wouldn't recommend not using
anti-aliasing if you want the text to look nice.
In any case, I see some that don't look too bad without anti-aliasing,
including Cantarell, the Droid fonts, and the DejaVu fonts. Have you looked
at those?
By the way, just want to mention: none of these are "Linux" fonts. I don't
think any of them were developed for the kernel Linux and not many of them
were even developed for the operating system GNU. Most were developed
independently by others and are included with many GNU/Linux distributions
because they are good fonts under free licenses.
