I think Kate is probably my favourite. She could kick butt, but she had her flaws too, which made her one of the more believable characters on the how.
I like Bishop just fine. Yes they overdid the quirky a bit to start with, but I think she has a ton of potential. I don't think there's anything particularly heinous about sitting on the floor - I do it a lot myself!
Ziva? She was fine to start with and then Brennan happened, and her character went completely down the toilet. By the end of season 10, I was so sick of her over-wrought, angst ridden melodramas that I was close to giving up on the show altogether. Happily Cote quit before I did, and I got my show back.
Jenny - Awful. Enough said.
Abby - One of the most annoying characters in the history of television, who I could quite cheerfully drop-kick into a volcano.
Of the recurring characters, Jackie Vance was my favourite, so I was beyond pissed when they killed her off for no good reason. I like Delilah a lot too - hope they don't leave her stuck in Dubai for too long.