Neo Destiny is my all-time favorite set. It's super expensive though eeee. :( But yeah, that gets my one and only vote. However I will say, Neo sets are generally my favorite among all, but Destiny takes the cake for me. All those Dark, Light, and Shining Pokemon...just awesome.
Going to break the Neo Destiny chain by voting. I prefer the Expedition Base Set, Best of Game, and Southern Islands out of all of these. I do like Neo Destiny, I just like these other 3 more, Southern Islands being the first miniset, Best of Game being the first time anyone in charge of the TCG actually printed promos with the intent of adding more copies of really powerful cards to the collective cardpool, and the Expedition Base Set because it was just so massive and has by far the best art of most Pokemon from the early sets.
I'm very unfamiliar with the Neo/e-Series cards which is a shame because I admire their art and style. I voted for Aquapolis and Skyridge because I like their names and the artwork from those two sets are possibly my absolute favorites of all the sets. I also voted for Southern Islands because the theme is really great and I would definitely like to get my hands on that set.
While not a fantastic set in my eyes, one of my votes went to Neo Discovery, since it was the last set I remember being heavily into prior to the end of Wizard's run with the TCG. I also voted for the Black Star Promo cards, since the Birthday Pikachu is one of my favorite cards I've never owned.