Visiting end of March ...need suggestions for dinner.
I would add Scampo in the Liberty Hotel for great food a place that has a good vibe. If money really isn't an issue and you want a truly unique dining experience then go to O-Ya but if you decide to try it be sure to call and reserve early and plan on at least $100. per person. If you enjoy excellent Japanese food you will love O-Ya.
That's a pretty wide open request. I'd suggest you browse this board a bit - you should quickly get a sense for the local favorites - and then come back with more specific questions.
Having said that, I'll toss out one must-eat venue to get you started: Craigie on Main, in Central Square, Cambridge. Great food, creatively presented, with an excellent wine list and savvy cocktail-making to boot.
Craigie on Main
853 Main Street, Cambridge, MA 02139