From season 5, episode "Identity Crisis"
David: Did you get her phone number?
Dinozzo: Courtney? Nah.
David: I did. (pause) She wants to learn how to fight.
There seems to be a whole lot of "is Ziva ever going to tell Tony that she's attracted to him?" and "is Ziva bi?" subtext going on.
Gibbs clearly feels paternal toward Abby, but I notice he's kissing her -- very fatherly -- more often since he started seeing Col. Mann. Maybe he's letting himself feel more emotions? Also, I like the developing relationship between Gibbs and Mann. She's the firsts lover he's had (that we know of) who isn't a redhead, which makes me wonder if the second coma and recovery actually was the start of him finally getting over the deaths of his first wife and their child. I had thought for a while that among the reasons none of his marriages or relationships lasted is that none of the women were Shannon. Of course, he's also an emotionally distant, sarcastic workaholic.
Jenny Shepard certainly seems to have mixed feelings. I think that the greater part of her is happy for Gibbs, and there's a definite undertone of "Colonel, if you break his heart I will fucking break you," but there are also strong undertones of jealousy. The scene in "Ex-File" where Gibbs found himself facing his ex-wife who is a material witness, his former lover who is now his boss, and his current lover who is heading his current investigation was, well, damned amusing from the outside. For once, I actually agreed with Tony -- "It's like a train wreck. I don't want to look, but I can't look away."
Also, if the theme of Season 4 was approximately "Too damn many secrets", then so far (four episodes in) the theme of Season 5 seems to be "All the hell kinds of chickens coming home to roost".
Finally, I have, gods help me, started reading NCIS fanfic. I've found one writer, KSL at http://www.ncisfiction.com/index.php , who doesn't make me twitch, and who actually manages to make Gibbs/Dinozzo slash seem plausible (to me; your suspension of disbelief may vary).