Thanks for the welcome Timewalker.
It would take me a while to make a more thorough list but for now I'd recommend (WARNING: NC 17) Five Senses by Witchsistah on fanfiction.net as one of the most well written 'romance' fanfics involving Data. This author has only written a few things as far as I can tell, but very high quality, especially for the topic.
Gotta admit, I'm really not into Data (or TNG, for that matter). I prefer TOS and Voyager stories, and clever/funny crossover stories.