I've only read a few Ouran fics, and the majority weren't that memorable. The one that really kinda stuck with me was It's a Wonderfully Splendid Magnificent Life (http://www.fanfiction.net/s/3311845/1/Its_a_Wonderfully_Splendid_Magnificent_Life) on FF.Net, which is mainly gen and pretty much all about Tamaki and his relationships with the other hosts and Haruhi. Dunno if that's what you were looking for, but I still think it's a pretty good read.