The true answer is all of them and more. I specifically made it obscure to work for many different series. I have come up with more series that could fit the scenario presented, but some of them would need work. There are two series that I made sure to work with the scene, but I kept in mind to keep it even broader to include more series.

With the numerous possibilities already posted, I may come back and add more as I watch more series. I wanted to use Escaflowne, but explaining that one would be a fan fict series by itself.

Taking out the comment about the girl's father and I could've added: Blue Seed, Devil Hunter Yohko, El Hazard, Fushugi Yugi and damn near every other series released with even the remotest romantic nature to them.

The point of this? It has a few of them.

One was to challenge the reader's preconceived notions. I wonder how many people took it for granted the couple was Ranma and Akane.

Two was to show the similarities between many series. Not just that the characters are all delaying romantic intimacy, but in some of the background between them. DNA^2, Ushio & Tora, and YuYu Hakashu would have the same opening paragraph to the second scene. In each case the girl's parents own a restaurant. Slayers also has that scene as it is reasonable that the part-time waitress/Ceiphied Knight works at her parents' restaurant.

Three, I hate it that some of these characters are beating around the bush. You know they love each other and they just won't get their act together and do something about it.

This is the second version. The first one had only six choices and the results were:

All -  240
Ranma 1/2 -  234
Tenchi Muyo OAV - 174
None - 154
DNA^2  - 147
Nadesico - 120
Ushio & Tora - 117
Patlabor - 114

Rather interesting results, but hardly scientific. DNA^2 got a lot more hits than I expected, but otherwise- I thought the distribution would look something like this.

Disclaimer: The various series presented belong to their respective owners, in which I am not one of them. I am only borrowing them for entertainment purposes. My poor little apartment couldn't take it if they stayed with me.

Go back and read the various answers.