In dance, I think it looks better if the male partner is somewhere around 5-6 inches taller than the lady. Any more than that and it is difficult to ge tthe lines matched up, and they also start looking more like a pair team, any less and it is difficult to do the lifts. However, there are exceptions to this. D&S (Bul) are close in height, yet they still manage to do really great lifts, and I think they look wonderful together. D&W (USA) have a really big height difference, but they disguise it with their incredible precision and unison and neatness. As far as body types, I think tall, lean, long-limbed dancers look the best, though even shorter dancers with longer torsos/short legs) can still look good if they pay attention to extension, posture, turn-out and toepoint.
For pairs, I think something around 6-8 inches difference looks good. In general, I don't like the look of most teams with huge height differences. B&S were an exception, they looked so well matched despite his being so tall and her so tiny. Teams that are very close in height tend to look akward in lifts, unless they have impeccable technique and positions. I don't like the ultra-thin partners like Zhang and Pang, but too curvy and sturdy is not aesthetically pleasing either. One thing I don't like about NNN/Themi is that she almost looks too curvy and muscular for pairs, I sonetimes find myself worrying about how he is going to get her up there on the lifts. Not that she is anywhere close to being fat, or large, or anything like that, she just looks really solid. Again, though, she has really nice positions in the lifts so that helps balance out the size. I think Brooke Castile is sort of the "happy medium", not rail-thin but still lean. I like that she looks like a woman, not a 10 year old girl.