I think that cheekies and boyshorts are the most popular. There are some girls that wear thongs but they are the minority that likes to show off their whale tail. I love love cheekies, I wear the ones from American eagle. I think they sometimes call them tangas also. Super comfy but still sexy. And not the end of the world if someone sees up my skirt on the stairs like it would be if I wore thongs.
It's different for every person. For me, I like to wear g-strings under things because it's less fabric up the butt. At night, since I sleep in underwear and a top, I like to wear regular full butt underwear or boy shorts. It's different for everyone and you have to get used to wearing different underwear. Hope this helps :)