The more I think about School Rumble and although this song may not be the one you think of immediately when you hear the words "School Rumble," it is probably the best OP/ED song of the series.  "Kono Namida ga Aru Kara Tsugi no Ippo to Naru" appeared as the first ED song of School Rumble Ni Gakki (School Rumble Second Semester) and is performed by Ami Tokito.  The translation of the song title equates to "because there are these tears, they will become my next step."  From my understanding, the song is about dreams being realized but one has to take that first step.

As for the series itself, I would recommend the first season over the second season.  Since this song appears in School Rumble Ni Gakki, I would say that the duration through which this song is used as the end theme is the better part of Ni Gakki.  I believe that Ni Gakki ended rather weakly with San Gakki (Third Semester) being worse since it's only two OAV episodes.  It's still a fun series to watch as it seems to form those groups of which ship (relationship) to support (i.e. Flag, Riceball, etc.)

"Kono Namida ga Aru Kara Tsugi no Ippo to Naru" English Lyrics