According to this site, these were the top songs of 1929:

1. When You're Smiling - Louis Armstrong

2. Makin' Whoopee - Eddie Cantor

3. Singin' In The Rain - Cliff Edwards (Ukelele Ike)

4. College Medley Fox Trot - Guy Lombardo
Can't find this anywhere.

5. Pagan Love Song - Copley Palza Orchestra
Can't find a version of this from the Copely Plaza Orchestra, but here it is from the Victor Salon Orchestra:

And because I couldn't find #4, here's #6:
6. Louise - Maurice Chevalier

Only know the first three.