1. Hermione and Ron (Deathly Hallows Part 2) - This is the most awaited kiss in the whole series and I think they pulled it off perfectly. It had the emotional aspect covered and was in an iconic location.
2. Harry and Hermione (Deathly Hallows Part1) - Technically, the characters of Harry and Hermione didn't kiss, but the Horcurux's projection of them did, to make Ron jealous. This was definitely the longest and most graphic kiss in the series and it was very well done by showing just enough to get the just of what is going on.
3. Ron and Lavender (Half-Blood Prince) - This kiss was pretty spontaneous and glanced at fairly quickly with no real emotional strings, but it was still effective. This was debatably one of the first things that made Hermione realize she was jealous of Ron when he was around other girls. It is a very realistic kiss between teenager.
4. Harry and Ginny (Deathly Hallows Part 1/2) - Technically, they kiss twice between these two movies, but since they are rather short kisses and these are two parts to one movie, I will include them together. These are completely normal, average kisses, but that's why I liked it. Neither one of them planned it, it just happened. It is the only way the movies really showed that Harry and Ginny were still together, and it worked well. A huge improvement over their first kiss...

(DHp1) (DHp2)
5. Harry and Cho (Order of the Phoenix) - I really didn't care for this kiss. It was very hyped up, but nothing really happened; their lips were only together for a second. In the book, it was much more exciting and in depth. They just kind of threw in the kiss because they needed to please fans. They cut out the whole Harry/Cho date fiasco, so this is really out of nowhere. It wasn't horrible though, like the last kiss on the list.

6. Harry and Ginny (Half-Blood Prince) - Where to begin with this kiss. I hated this kiss. It was so poorly executed. The actual liplock lasted for about a quarter of a second, and it so hyped! It was the only way the film set up Harry and Ginny's romance, which I would have understood if they followed up the romance, which they didn't. It's really a shame how bad this kiss is because this is one of my favorite Harry Potter movies.
So there it is, my list of all the major Harry Potter kisses and my order of preference.
Agree with me? Disagree with me? Did I leave anything out?
Comment and let me know! Thanks!