While Georgetown is a fine place for a walk, it's not really a great part of town for restaurants. There are some good places in the West End (i.e. near Foggy Bottom station) but the hot spots are more around Logan Circle / Shaw or Capital Hill these days. And there are some good places to eat in Crystal City itself, which has gotten artier and more interesting these days.
A possibly useful transit note is that Arlington Transit bus ART 43 runs from Crystal City to Rosslyn (and Court House, which is a short walk to Clarendon, which has some good restaurants, though less interesting ethnic places than it used to). I work in Crystal City and use it as an alternative during track work or other rail screw-ups.