Another vote for Tru: in my view, its the best place in town, with great food and very quiet, pleasant atmosphere. But, as mentioned above, it is extremely expensive, and dinner lasts a long time (many courses).

I don't think that Spiaggia is all that romantic; its on the second floor of an office building, and while the food is very good, it has something of a business dinner feel. (The cafe next door is much more relaxed, but not a good romance destination).