I'm currently in the middle of season 7 of TNG, and I've come to a conclusion. While I still believe that Captain Picard is the best captain (I haven't gotten to DS9 yet), I find that my favorite character is Data. The episodes which focus around his growth and development as a character are some of my favorite. The episodes which center around Warf are also quite enjoyable.
I find Troi to be the most annoying character, particularly in the first season. She gets a little less annoying annoying as the series progresses, but ultimately I found that she didn't really contribute much to series outside of general sex appeal. As a character, I think that Tasha Yar was a much better contribution to the cast and story, though they killed her off rather quickly (This is due to the actress. However I wish they hadn't simply killed her off.) so they weren't able to develop her properly.