The most popular choice is the little black dress which is a must have for every wardrobe. It can be worn for every event, occasion and season, dressed down or formal.
If you are looking for a , light and airy, summer dress to make you look hot but not overdoing it at outdoor parties like a holiday vacation or an upcoming barbeque party, then you can go for a halter neck style or a maxi dress.
If you have a prom/ball or formal dinner to go to, and you have decided that you want an elegant and classy dress but is very unique also, then you have a long list of choices for you such as strapless, backless, long to knee length, corset, etc. And the trendy look of defined waistlines and displayed shoulders is very girly and flattering to almost all body shapes.
If you want something less formal, then you can just go with what dress is considered at the latest trend, which is forever changing all throughout the season.
As you have noticed, you have a lot of options available to you. Go check out what the red carpet celebrities are wearing to find an inspiration.