Ecruteak is a great pick. It's probably in my top three. I love the classic Japanese architecture, the autumn mood in the DS remakes, the lore with the three gerbils and Ho-Oh, and Morty.
My other two picks (not sure how to order them) are Fortree City and Lavaridge Town. Lavaridge is really small, but I thought the hot spring was so charming. I wish it had more, but I still loved to visit there all the time on the GBA games and save the game there. Fortree City was also really creative to me at the time. I mean, who doesn't wanna secretly live in a treehouse? I too loved the bridge sounds, as well as the surrounding routes. I always had my Secret Base be on the left bottom route between Fortree and Lilycove because it had cute puddles nearby, a pond, and four berry patches for me to farm 99+ berries. I was so mad when they screwed that base up in the 3DS games...
Overall I don't really like the ORAS remakes. I hate the stiff animations from the characters; the 3D design still feels cheap even if it's slightly better than XY; I feel like the region loses more charm than it gains. I thought FireRed and LeafGreen were all right for Kanto (they made some weird decisions, but the game still looked good and kept the feel of the region for the most part), and HeartGold and SoulSilver are my favorite Pokemon games. I'm playing Silver right now, and you can see how much charm they added to the DS remakes (besides making some quality of life changes like the berry / apricorn stuff). With Fortree and Lavaridge, the towns may not have been that big, but they were cute and they were on the GBA. I feel like the 3DS games could have added more flavor to both, just like they did with Ecruteak and the autumn colors, but they really dropped the ball. I think it disappoints me so much because I was so impressed with seeing real color in a Pokemon game back in the GBA era. I thought ORAS could invoke the same feelings of awe when going into 3D, but the transition has been real weak so far. At least Sun and Moon look decent. /gen rant