^ there are probably more interesting mangas I'd recommend to you then Natsu no Arashi, because at least to me Natsu no Arashi starts off quite slow, things didn't really get interesting to me until the last quarter of season 1 of the anime.
Even at that point the anime they were still introducing new characters, so it has a bit of a slow build up introducing characters and telling you a little bit of back story for each one etc...
Season 2 was a lot more interesting because there weren't many new characters to introduce, and the ones that were introduced were mainly minor characters.
If I were to recommend a manga to you, then I'd recommend "The World God Only Knows"
It's nothing like School Rumble, except maybe the Genre... Google it for a summary, I'm never good with summaries.