A Day to Remember by richefic is a Gen NCIS fic with a strong emphasis on the father/son relationship between Gibbs and DiNozzo. Starts out with Tony having a bad day that only gets worse as it progresses, and he and the rest of the team have to deal with the consequences. Richefic does an excellent job of capturing the voices of the characters. Story is set near the beginning of the series, so Kate is there and McGee is definitely still a rookie agent.
Myths and Revelations by Nix (crimsonquills) is NCIS (Gibbs/DiNozzo), but with a twist. In this AU, centaurs exist, and Gibbs just happens to be one. The series begins with Tony discovering Gibbs' secret. From there, they hesitantly begin a relationship. There are very interesting dynamics between the characters, as centaurs have some distinct differences from humans (beyond the fact that they have two forms--human and centaur). Very intriguing series. The first stories deal mainly with the centaur secret and the budding relationship between Gibbs and DiNozzo (and then the other team members' reactions to both), but the latest story (#12) is a really mystery.