LinuxTag used the DIN font for years now. Originally, it was proposed by the people from newthinking communications, who were doing our advertising stuff then (hey, how are you, people?). It was and still is a nice font, but it has the problem that it is not freely available. We're having a hard time licensing this stuff for all peope using it in creating our materials.
I think it is time for a change. Unlike then, a vast deal of quality free fonts are now available. Two fonts which I am currently looking at are "Delicious" and "Gentium".
Delicious is a light, sans serif font made by Jos Buivenga. It is light, modern and perfectly legible for headlines and continous text.
Gentium is a serif font by