#4 - Kimi ni Todoke
All of these are going to be spoilers I guess. Under the break.
#4 - Kuronuma and Kazehaya
These two make the list as a good example of something that doesn't happen often - a couple that are extremely happy to be a part of each other's worlds. The drama in Kimi ni Todoke is really subdued which helps, but these two are pretty damn adorable. These two completely care about each other and want to be part of each other's lives no matter where or when. It's also really nice that they are both that way. There are a lot of main characters in shoujo like Kuronuma but rarely ones like Kazehaya.