We recently went to Bar Americain and had fantastic food, service and cocktails. Pretty priced but worth it. Everyone loved everthing.
A new Nobu called Nobu Fiftyseven opened in midtown as well. Haven't been there myself but I heard great things. Couple of friends were raving about it this past weekend. Owned by Morimoto, the Iron Chef dude.
For a good seafood restaurant that's super close to Grand Central, you can try Dock's over on Third Avenue and 40th Street. Haven't been there in a while, but I had always enjoyed it. Really good martini's!
A NYC staple on the restaurant scene is the Oyster Bar which is on the lower level of Grand Central. NOT fancy, but fantastic seafood, great atmosphere although loud. I love the place.
If you're looking for a GREAT little known (to tourists) Italian restaurant, you should try Osteria al Doge. If you plan on going just prior to a show, you need to make reservations asap because this place fills up. GREAT food, really nice place. Excellent service with good Italian wine. It's on south side of 44th just off Broadway in the Times Square district.