Yandere can be nice for humor but few of my best girls fit the type. They're also comparatively rare. The only ones I can think of I've seen are Tsukihi and Marika, both of which were mainly comic relief characters (Tsukihi is only mildly violent while Marika isn't violent at all).

I like certain kuudere's and dislike others. I hate ones like Rei and Shiina, you know, ultra-submissive otaku fantasys with no personality (now I do respect Rei as a character, but I don't consider her best girl material). On the other hand, Yukinon is an example of the kuudere done right. She has a will of her own.

Tsundere is also hit and miss. I really hate tsundere's where the progression is total bitch -> submissive housewife fantasy. People often justify them on their dere side, but for me they were obnoxious before and plain boring afterward. Taiga is the worst offender here. Asuna less so, she at least wasn't particularly violent and obnoxious when she was tsun, but she does become submissive and boring I dere mode.

I always like my tsundere's to retain a little edge, to be a little devilish (as you can probably tell by now, I despise submissive love interests). So, Rin and Inaba both come to mine as examples of the tsundere done right. Neither was ever particularly violent or obnoxious and they always retain a little devilshness. I also really like Tsugumi, I can't justify that because she is hyper violent but I just can't help myself (perhaps it's because her violence more comes from her profession as a bodyguard and a sense of duty rather than being an inherent part of her personality).

I am a huge fan of the "bitch in sheep's clothing", inverted tsundere, like Ami from Toradora and Tsukasa from Amagami SS. But, they are comparatively rare.

As for dandere, I honestly have trouble picking them apart from kuudere. Mostly I only run into them because I've classified someone as kuudere and someone comes up and is like "No, that's a dandere!" I guess I have to watch now anime to see more examples where they were clearly differentiated.