I'd say Truffaut...not only for his films (which any argument for Godard's films one can make for Truffauts...the cheekiness, the clunkiness, etc) but also for his days as a critic...here was a guy who was vitriolic and scathing in his criticisms of films he disliked, and affectionate and passionate about the films he loved...he came up with the "Auteur" theory (a director should leave his own personal mark on every film)...some of his articles helped the careers and critical viewpoints of such directors as Ophuls, Hitchcock (who was pretty much considered a "talented haack" before Truffaut), Sam Fuller, Louis Aldrich...he also tried to help his upstarting friends make their films (he wrote the original story that became "Breathless", for example)

As far as his films are concerned...I'd also make the argument that he NEVER sold out....where as Godard was trying his hardest to prove how much of an "anarchist" he was, Truffaut went more for the kind of subversion that Hitchcock was known for....take a regular Hollywood-type of storyline and expose the rot underneath just enough to get the audience uncomfortable not only with the movie, but aspects of themselves they see on screen..

yeah, I'd see "400 Blows" over "Day For Night" any day of the week, but that's not say I wouldn't wait in line to see "Day For Night"...yeah he got more technically proffient over the years, but so does anybody who loves their craft.....

As far as Godard, a friend of mine who REALLY loves him put it best when he said "Truffaut made films....Godard makes Thesis"...I guess I'd rather watch films...